http://xbox.ign.com/articles/394/394163p1.html
Heres a tidbit of it. The most important stuff
"Two new maps, usable only for Capture the Flag, will be available for download with CTF as will two brand new mechs. The new maps are quite different from one another. Midtown Mayhem is another city map, but features rolling hills and some valleys to hide in. Desert Storm is a much cooler version of the wasteland maps previously on the MechAssault disk. With heavily blowing winds, several bridges, and some long drops, this one is actually up there as one of my favorite maps available.
The two new mechs, the Loki and its variant the Hellbringer, are powerful beasts that can stand toe-to-toe with the Atlas and possibly even the Ragnarok. And the Hellbringer comes with extra goodness in the Flamer gun, which offers some major burn damage.
The newest MechAssault downloads, available in three weeks time, will include some upgrades to the overall MA online experience. Now when a game is finished, instead of being kicked to the general lobby, all players will be brought back into a game lobby. This way you can keep playing with the same people, but change up the game modes and options any way you like. Also, whenever someone talks, their name will now flash onscreen, so you can see if it's actually your own teammate crying for an assist."
