Steve Ballmer, never one to pass up the chance to shoot his mouth off, apparently spilled the beans on Halo 3 all the way back last fall at the Microsoft Office 2003 launch. It went unnoticed until Richard Watkins found it and told Louis Wu at HBO. Of course, that doesn't necessarily means he knows it for sure; the statement might have been made predicated on the idea that MS would never let a good title go unfranchised:

We're working on the next version -- I hate to tell you this confidentially but I'll have to swear you to secrecy now -- we're working on the next version of Xbox right now and we're working on Halo 2 and Halo 3, the two newest versions of the game.

Incidentally, we wonder how useful it is to swear anyone to secrecy, and then place your statement in a document posted on the web. Perhaps Ballmer doesn't quite get this 'Internet' thing yet.