It fully integrates with S2U2 & supports A2DP & AVRCP as well.

S2P now simply uses the device's built-in music decorder WMP.

Installation:
- Under your PC/MAC/device, extract the content of the downloaded file & copy the CAB file to your device.
- Under your device, run any File Explorer application; go to the folder where the CAB file is copied; run the CAB file.

Download:
- QVGA CAB file (227 KB) or its mirror here.
- VGA CAB file (253 KB) or its mirror here.
- OpenGL VGA version (258 KB) or its mirror here for Touch Diamond/Pro/HD & Xperia X1.

Operations:

• Since S2P simply scans music files in your storage card, it's suggested to have your music files well organized by folders. So that you can browse your music files through the folders instead of a plain list. (e.g. \Artist Name\Album Name\Music title.mp3)
• When browsing, press the folder name to list all music files under that folder, including subfolders; or press the arrow button to list the subfolders.
• Press any one of the filename to play.
• To go back to the music file list, press the top left back button.
• To view the current album list, press the top right icon. Then press any one on the list to play that music.
• To go back to the single music view, press the top right icon again.
• On the single music view, tap the screen to call up the timeline. Press the left repeat icon to repeat the current playing album; press the right shuffle icon to play the whole music list randomly. When both icons are on, only the current album will be played randomly.
• Under the music playback screen, slide up or down the edge of the album art will change to the Album View screen. To go back to the normal playback screen, slide up or down the edge of the album art.
• The hardware keys are:
  End - minimize
  Vol Up/Down or DPAD Up/Down - volume control
  DPAD Action - play/pause
  DPAD Left/Right - previous/next
  Left/Right soft key - previous/next album
  Power/Record - turn screen off

Please read the README FIRST for details, especially the Known limitations & FAQs.

Update Description:
v0.58 (04-12-2008):
- More finger-friendly on the Album View.
- Added option to repeat a single Album, so the repeat options are: none -> all -> an album -> a song.
- Added option (ShakeThreshold) to adjust the shaking responseness.
- Added limited support to HTC Wired Remote Control (read the FAQ for details).
- Added an OpenGL version for devices that support OpenGL ES (Touch Diamond/Pro/HD & Xperia X1).
- Fixed on some devices S2P crashes when Bluetooth is already turned on (but AVRCP still may not be supported on these devices).
- Fixed when shuffle is on, sometimes the Album pic cannot be shown.
- Fixed when repeat option is on, the "slide to next Album" does not work.
- Some minor bugs fixed.
- One known issue left: Album View will crash when there are a lot of albums (> 8G of songs).

v0.55 (25-10-2008):
- Added option (AlbumLayout) to have different position of Album displayed.
- Added support to HTC Diamond's shake gesture - ShakeAction: 0 to disable; 1 to go to next song; 2 to go to next shuffle song.
- Added support to switch to Album View if your device has a button for changing orientation or a slide out keyboard.
- More "even" shuffling on playback.
- Auto-pause the playback when headphone (either Bluetooth or wired) is disconnected (need S2U2 running in the background).
- All graphics support high resolution, i.e. truely VGA.
- Simplified the AVRCP trick for Diamond (no need to manually start WMP).
- Fixed the system speaker issue when the playback is paused & resumed after a while.
- Some graphics changed.
- Some minor bugs fixed.

v0.50 (15-08-2008):
- The Album View now can flow. (since this view is very CPU intensive, it may be sluggish on your device)
- Added 2 control buttons in the Album View.
- Added option (FastAlbumPic) to retrieve embedded album pic faster (same as v0.38); but if the album pic cannot be loaded probably, disable this option.
- Changed option AlwaysLoadAlbumPic to AlwaysLoadEmbedAlbumPic; it's only useful when a folder contains a mix of songs from different albums. If there is no embedded album pic in your song files, make sure to set it to 0.
- The album pic & song info are now cached (under each folder as folder.jpg, s2p1.tag & s2p2.tag), i.e. the second time you visit the same album, it'll be faster.
- Added support to HTC Diamond - both GSensor & AVRCP; for AVRCP, read the FAQs below for the detail trick.
- Added support to RealVGA.
- Won't keep the system alive when it's paused.
- Separate CAB files for QVGA (low-res) & VGA (high-res) devices.
- Fixed the issue that all memory was ate up for some problematic embedded album pic.
- Some minor bugs fixed.

v0.41b (beta):
- Special build for HTC Diamond; support GSensor (thanks Mr Scott Seligman) & AVRCP, read the FAQs below for the details.
- Some minor bugs fixed.

v0.40 (02-05-2008):
- Added AVRCP support (play/pause/next/previous) to devices that use MS BT stack.
- Added DPAD control to "move" the playback when the timeline is shown.
- Added "Repeat Single" - tap the repeat icon until a small "1" is shown.
- Limited the way to change to portrait Album View by double tap the album title area only; to go back, double tap the album title area again.
- Fixed the issue that some devices cannot run in Landscape mode.
- Some minor bugs fixed.

v0.39 (09-04-2008):
- Added option (NoSoftKey) to hide the bottom soft music control keys.
- Added to show Album View at portrait mode by double tap the screen; to go back, double tap the screen again.
- Now runs properly with RealVGA at 96dpi.
- Rearranged some keys - END/OK to minimize; ACCEPT to quit.
- Fixed some embedded album pic problems.
- Some minor bugs fixed.

v0.38 (31-03-2008):
- Reduced the RAM usage, especially when there are a lot of music files on the list.
- Reduced the start up time.
- Added option (FullScreenAlbum) to display a larger album art. For 240 x 240 device, please set it to 0.
- Added a sliding button to "move" the playback.
- Added minimize S2P by tapping the top right corner of the screen.
- Rearranged some keys - END/OK to quit; ACCEPT to minimize.
- Integration with S2U2 v1.00 or later (read the S2U2's readme.txt for details).
- All system icons are live when S2U2 (v1.00 or later) is already running in the background. (but it doesn't mean S2U2 is mandatory).
- Runs properly on a 320x320 emulator, but not tested on any real 320x320 devices.
- Some minor bugs fixed.

v0.32:
- Fixed the issue that S2P did not start due to some problematic ROM/OEM.
If it still not work, pls download & install the WMP-OCX-fix.cab (for WM5 square device, pls try the WMP-OCX-WM5-square-fix.cab). v0.31 (17-03-2008):
- Changed the music decorder from MAD to WMP, so no more OGG support, but now preliminarily supports WMA.
- Added Album View screen. Under the music playback screen, slide up or down the edge of the album art will change to the Album View screen. To move to previous or next Album, tap the adjacent albums. To move faster, slide to left or right. To go back to the normal playback screen, slide up or down the edge of the album art.
- Added option (ResumeAfterCall) to resume or stop the playback after a call is finished.
- Added support to load Album art of WMP (Album*.jpg).
- Added minimize S2P by pressing OK.
- Added Landscape support: Under whichever Portrait or Landscape mode, the music playback screen will always in Portrait; and the Album View screen will always in Landscape.
- Added more power saving for AVRCP: Normally, when an AVRCP command arrives, the LCD will be forced to turn on even it's offed. Under the same condition, S2P will turn the LCD off immediately.
- Changed the layout a little so that the whole album art will be shown.
- Smoother animation.
- A lot of minor bugs fixed.

v0.17 (27-02-2008):
- Added preliminary AVRCP support to those devices use Broadcom BT.
- Further lowered CPU usage when minimized, about 50% of the previous version.
- Added option (SaveLastMusic) to reload the last playing music. (read the Settings section below for details)
- Added option (AlwaysLoadAlbumPic) to always load an album art for each music. But if you've already organised the music files in folders, it's not necessary to enable it so as to safe battery life. (read the Settings section below for details)
- Fixed cannot retrieve some ID3 embedded album arts.
- Some minor bugs fixed.

v0.15 (25-02-2008):
- Added volume control by DPAD Up/Down.
- Added ID3 embedded album art.
- Lowered CPU usage when minimized.
- Fixed occasional file name mismatch issue when navigating.

v0.12 (22-02-2008):
- Added album navigation keys - Left soft key to go to previous album; Right soft key to next (besides, it can also be done by sliding the screen to right/left).
- Fixed the single channel problem on some devices.
- Fixed the slow response of the on-screen volume control.
- Lowered the screen refresh rate (should help some slow devices).

v0.10 (20-02-2008):
- Initial release.

SOURCE

http://forum.xda-developers.com/showthread.php?t=417511

Reviews:

***** [Feb 24, 2009] by eddie using samsung omnia
Great job. I had only one question, when I was playing a song the blue time countdown bar just stood there and makes me get a bit annoyed.. :p any solution?

***** [Nov 13, 2008] by Jhony using tmobile wing
Best software I've used so far...

***** [Nov 4, 2008] by 594688609 using 838
I love it. It's cool.

**** [Aug 26, 2008] by Hayden using Cingular 8125
Great app! Works quite well with S2U2. And it looks very good. The only reason it's four stars is because it lags. If it's the only app running, there is almost no lag. But with Pocket Word and GSFinder running, this will lag enough to become a bit annoying.

***** [May 29, 2008] by S_C using ipaq 214
This is really awesome and is now my primary player, only minor issues I have: Sometimes, the tapping is not very responsive and you have to tap/wait a few times. Double tapping the song title does not work for me because of the above, i have to keep tapping the screen until somethng happens. Again, because of the above, sliding is also not 100%. Sometimes, I am sure I tapped correctly (there is an art to this) but things like song title screens take a while to do something. I have a fairly decent specc'ed IPAQ214 and even running only this application, I still get the above issues. Other than that, everything is ace.

**** [May 8, 2008] by spos5 using HTC TyTn
Best player yet. Ready for primetime.

**** [May 7, 2008] by Glenn using hw6900
Works well esp with s2u2 & pointui... only thing not working for me is the control (eg pause next etc) from my bt headphones...

* [May 5, 2008] by w using HP iPAQ HW6945
Still not working on iPAQ 6945 and developer seems to ignore users with this problem. Makes the system freeze.

***** [Apr 17, 2008] by Luis using 8525
Love it the only bugs are that it automatically turns off the screen after 10 seconds, and that it doesn't always respond well to some taps. But otherwise its rocks.

* [Apr 15, 2008] by e using iPAQ HW6945
New versions don't work on iPAQ 6900 series. (v. 17 used to work)

***** [Apr 14, 2008] by Mitch using HTC 6700
So much awesome my face hurts. Seriously. It would be my Primary player if it supported AVRCP on the Windows bluetooth stack. :(

***** [Apr 12, 2008] by AMAK using HTC P3300, WM6
Excellent development. The only issue it is slow when switching from one screen to the other. Since it remember's its last possititon, this problem is not a big deal. Well done.

***** [Apr 12, 2008] by tom using x51v VGA wm5 624mhz pxa270
Can't reiterate enough how tight this is! Unfortunately, a few bugs still:
- 6 seconds of silence/processing to change tracks;
- Bigger dirs of songs fails to flip over to display tracks.

Can't tell you how much I want an Intel 2700G optimized version! Or a gsplayer base rather than wmplayer... Still - this is a GREAT piece of work. Solid... has not crashed yet.

***** [Apr 11, 2008] by tom using x51v vga 624mhz
AMAZING!! TOTALLY tight. Unfortunately, on x51v (Dell vga pxa270 624mhz) is a little slow. In particular, flipping the album over to view the songs… can be quite frustrating. Can’t tell if it registered your click on it… it just sits there at times. But totally badass.

***** [Apr 3, 2008] by Zaiaku.com using HTC 8125 Wizard
The update seemed to have fix the space error bug. Works much better for me. Thank for the update!

**** [Mar 10, 2008] by Zaiaku.com using HTC 8125 Wizard
Works great and very easy to use. Although wish I could still access the system volume while this is running. I have to go bacc to the today screen to raise the system volume. Would love to thi this developed more as is great right now, could be outstanding.

***** [Mar 3, 2008] by John using i760
Wish development would continue seems like great potential.

**** [Feb 27, 2008] by ACCHO using HTC Touch
Good for 2 simple reasons: (1) simplicity (2)Play by folder & remembered her last play folder position . For the latest update does not seem to work properly on HTC Touch . good job already. could MIDI be included?

***** [Feb 26, 2008] by cbsim using O2 XDA ATOM EXEC
So far, I enjoy using all the program (S2U2,S2V,S2P) from A_C, however it would be great if song seeking is supported in S2P.

***** [Feb 23, 2008] by Teseo using eten glofiish m700
Applicazione stupenda! Mantiene in memoria l'ultima cartella aperta anche dopo un soft-reset. Applicazione completamente gestibile col semplice uso delle dita. Al momento, a meno che non mi sia sfuggito qualcosa, non c'è la funzione per andare avanti e riavvolgere la traccia velocemente, ma francamente non la uso mai e quindi poco male. Consiglio a tutti di installarlo tanto più che non è necessario installare altri applicativi quali S2U2.

***** [Feb 22, 2008] by acrylic_26 using Hp 6828 window 6
Wowww!!! What a great app, but I couldn't drag foward while playing mp3. How to do that? Also S2U2 also more stable.