milesmowbray released an update to his YouTube search and player application Youtubeplay. It feels a bit like CorePlayer.

Youtubeplay allows you to search for videos in a nice friendly Windows Mobile 5 (and greater) application and then plays the full FLV video (not miniscule MPEG4 versions) with its own player. This application can download the FLV videos for offline use and also then extract the soundtrack to an MP3 file.

The app is written in a mixture of .net and C so you need the .net runtime, v2 or v3.5. The video player overlay is hacked out of TCPMP and the FLV part is based on FFMPEG.

Changes:

New – Added the facility to extract the audio as an MP3 from any saved FLV
Fix – HTC Streaming Media option should now work again

http://forum.xda-developers.com/showthread.php?t=385227