The Halo 3 Beta is dated for May 16th at 12am through June 6th 12pm, according to Bungie.net. Now they have gone and released this multiplayer vidoc "Is Quisnam Protero Damno!" that shows a few new things like the shield grenade, trip mines, and talk about the revised battle rifle. Check it out.
I am soooo ready for this game. Bring on the all night frag-a-thon! Guess I will have to settle for a little Halo 2 for now ;)