Peter Jackson's new Halo game is currently already in production, according to Bungie's Frank O'Connor. Last year Jackson and Microsoft formed Wingnut Interactive Games Studio in Wellington, New Zealand, to work on the Halo game and future projects.
Most notably, O'Connor reveals that Bungie has already dispatched designers and engineers to Wellington to work with Jackson on the new Halo. Developers from both studios (Bungie and Wingnut) communicate and collaborate, via email and conference calls. Jackson's Halo will feature a new story and will not be a continuation of the plot from the first three Halo games.
O'Conner also says that Microsoft hopes Halo 3 will earn US$155 million in a single day - besting the US$151 million opening weekend set by Spider-Man 3, the current record holder at the US box office.