I did this this past weekend and it was pretty easy, though it took me more than 30 minutes!
Here are the details:
http://www.productwiki.com/microsoft-xb ... nutes.html
Now I can sit on my couch and use the XBox to access my iTunes library, watch slide shows of my digital pictures and even stream videos I've downloaded. And the Xbox will still play games and DVD's like normal.
Definitely worth the effort.
T.