After making people wait till 2AM (pacific) Bungiefinally posted ( that there's a slew of new Halo things on the way.
New multiplayer maps for Halo 2 (also you need an Xbox 360 to play)
Halo 3 commercial during Monday Night Football on December 4th. The game won't feature any in-game footage, but is being created from by Digital Domain. It'll be all-CGI using Bungie's models and and assets, and will feature new music from Marty O'Donnell. After the commercial airs on TV, it'll be available in the XBL marketplace along with the next installment of Bungie's "making of" Halo 3 documentary.
The biggest news by far has to be the announcement, Bungie will also be holding a public beta for Halo 3 sometime in the Spring, public multiplayer demo hitting Xbox Live this spring, which will give millions of fans a taste of things to come.