For all your media playing needs VLC media player is a wonderful choice. This player will play just about any media you throw at it as well as it's an excellent choice for those who need a media server. You can learn more about it and download it from here: http://www.videolan.org/vlc/
Also just for your information, do to this media players high level of portability there are versions of it for just about any computing platform even WinCE/PocketPC. 
