According to the man who was hired to direct it, the Halo movie is completely dead. Neill Blomkamp, who has been working on the project for the past few months, says that it's all due to the fact that the two studios, Universal and Fox, that are putting the film together are too far apart to make the project work.
In addition, Blomkamp has put to rest rumors that the short films that are part of the Halo 3 ad campaign have anything to do with a potential film. They don't. He maintains that nothing in those shorts bear any resemblance to the work he has done for the film.
Sorry, Halo fans.
GamerNode: Halo director says movie is dead