In the wee hours of Wednesday, Feb 20th, PST, the Halo 3 AutoUpdate will go live, and address some minor bugs and gameplay issues.
The main change many players will see are to do with Melees. It is now possible to both die during a Melee (judging by alot of players playstyle this will now happen often) if both players have similar health. Bodies that have just died from a melee now do not fly miles and should be more realistic. Whether this is a good change has yet to be seen.