Here's the scoop right now... The only facts that I have been able to fish out about the new halo game, is this:
Fact: It is going to be coming out sometime in 2007, the exact date will probably be named at some big gaming convention (prolly E3 or something.)
Fact: The graphics are going to be insane!
Fact: This is going to conclude the story of 1 & 2, but it probably isn't going to be the last Halo game you will ever see.
Fact: It is going to be made ONLY for XBOX 360, but considering that this game will more then likely not hit shelves till Christmas time of next year, this will give you enough time to save up some cash.
I wish that I could tell you more facts about the game, but I will be keeping my ears open about this game.