yeah you can use mouse and keyboard for xbox.
http://www.lik-sang.com/info.php?products_id=5438
I would get mine but my xbox is shot right now so, dont wann waste me money lol.
Halo 3 is basically gonna be everything that h2 wa suppose to be. All of the promises that they had out, they will be added in h3. I am hoping they make h3 more like h1 because h2 was suppose to be this real big deal and when it came out, it wasnt as good as it was anticipated. h1 was the greatest and will always be the greates.