Well, its offical, Bungie has announced a new game for the Fall of 09. Its called Halo 3 Recon, and the idea is that we are ODST (Orbital Drop Shook Troopers) and are on a secret mission. It takes place between Halo 2 and Halo 3, especially when the Prophet Truth jumps into slipspace in New Mambosa. We are deployed and from there everything is speculation.

You can check the trailers on Bungies offical website or Halo 3 forums website. Use this thread to make predictions, thoughts, etc. Im really excited for this game.