Nitrogen Player - Microfi Nitrogen is a native Mobile application (unmanaged code) that allows you to play MP3 songs stored on your mobile device. It features a file browser, full skin support, "Shuffle" and "Repeat" modes, a built-in sleep mode and a command to blank screen to prevent energy waste while playing music. Nitrogen uses the MAD decoder, which is opensource. As the official releases of MAD for Pocket PC seem to be discontinued, Nitrogen uses the libraries from an opensource player (GSPlayer).
Duomi 3.6.0.00 Duomi 3.6.0.00 - Duomi Chinese Java Music Player
For Nokia X2-01 S40 Series 320 x 240 J2ME
MP3/WMA/AAC/MID/AMR / M4A/ogg/flac/mp4, format (Or so I think. :/)
As you can see here and from the screenshots this is the Chinese version I think...or so that's what Google said when I tried translating it