It depends on the format of the files you have ?
If you mean a CDG disk - you must rip the files with audiograbber (on the PC)
Use MP3+GToolz (also on PC) to convert different formats
You need the files as mp3+g
that is >
mysong.mp3
mysong.cdg
Copy both files to your xbox, enable karaoke or CDG (can't remember the menu - but you'll find it - music settings ???).
then play the mp3 file and hit X to switch to visualisation mode and the cdg "words" will be displayed

You may have to fiddle with the delay in the karaoke to get the words to lightup at the right time
Good luck and enjoy
