Thank you all, ill try a few of these out. They should put windows media player on the xbox, would be so much simpler.
No transcoding links please as I've tried a few of them and they all suck.
So erm, you want to do transcoding but don't want any suggestions about transcoders? If I ignore that comment, I'd recommend ...
Handbrake - easy to use, almost 1 click transcoding.
Ripbot264 - easy to use, does x264 video can't remember if the Xbox plays it / what profile to use
(edit: fyi transcoding simply means the conversion of one type of encoding to another, e.g. MPEG2 to x264)