Source: The film rumor and news site IESB.
The official story: Microsoft and Universal reps have not responded to requests for comment. 
What we heard: Earlier this year, thousands of nerds' heads exploded when they heard the rumor that Peter Jackson was going to direct the film adaptation of Halo. While that turned out to be false, the Lord of the Rings director did sign up to executive-produce the high-profile project, which is being cofinanced by Fox and Universal.
Since then, speculation has run amok about which filmmaker would be entrusted to bring one of gamedom's holiest of holies to the big screen. This week, IESB claimed to have a possible answer. According to an IESB reporter named Chupacabra, as in the famed Mexican vampire creature, word was leaked at the recent King Kong press junket that Jackson is in talks with famed Mexican horror director Guillermo del Toro to helm Halo.
It's not surprising that Jackson and del Toro would collaborate. Both have similar backgrounds, having made their bones in horror (Dead Alive, Chronos) before moving onto big-budget blockbusters (Lord of the Rings, Blade II). Also, both have shown dramatic flair and characterization skills in the art house thrillers Heavenly Creatures (Jackson) and The Devil's Backbone (del Toro).
So will del Toro direct Halo? If he is indeed in talks, that will depend on two factors: First, whether he wants the job. Second, whether Fox and Universal executives are comfortable with a director whose last project, Hellboy, performed below expectations. Given Halo's high profile and del Toro's self-professed love of games, the answer to the first question would almost certainly be "yes." As for the second, the executives in question might do well to remember that Jackson's sole Hollywood project prior to Rings was the box-office dud The Frighteners. We know how that turned out...
Bogus or not bogus?: A del Toro-directed Halo would be visually interesting, at the very least.