Yes, Mainly music files, You can only transfer mp3 and wmf format. You can trasnfere Jpeg (picture) files also Xbox karaoke songs (www.xboxkaraoke.com) You cannot how ever transfer files of a different kind EG soft modding your xbox! The program will not allow you too,
I've found out another thing, when you have copied them across (I use mp3 fles personally) you would think that you can only use music mixer to listen to your music......WRONG, there is a selection where they can be recopied on the Xbox Hard drive to be configured to the point where you can use them for the custom soundtracks in games. Pretty cool huh, how you do it you from the main menu is
Music Player---------Create/edit---------
You should now have alist of your soundtracks and you might notice the files you have transfered have "PC: " next to the artist name, thats because its transfered as unreadable file by other games. well anyway you then must hit "GAMES" at the bottem right hand corner of the screen, you should get a window saying
"Xbox music mixer needs to prepare this imported soundtrack for use with Xbox games. It could take several minutes, depending on the size of the soundtrack. Press A to prepare soundtrack for games now or press B to cancel"
I would suggest personally is to copy all your music over and leave that preparing option running over night, so when you get up in the morning (or afternoon in some of your cases) you will have your fresh tracks readt to play with your xbox games great huh??
Forgiveness is between them and God, I'm just here to arrange the meeting!!