I recently bought an Xbox (first generation) to mod so that I could run Xbox Media Center (XBMC) on it. Virtually all the information I found on this project assumed you had a PC, which, as a Mac user, didn't help me much. So once I'd gotten everything working, I decided to put together a small site showing how I did it using my Mac. If anyone has anything to add I'd love to hear from them via the comments.
Mac OS X Hints