It's in the works. 2012 is the expected release but since hardly anything has really been set in stone it could be wiped off the producers table at any moment. Though unlikely, just looking at it's predecessor video game trilogy gross. Universal already has it's script from 28 Days Later writer Alex Garland and Peter Jackson is a stable producer.
Then again, very few video-game based movies turn out praiseworthy. Cross your fingers.
Check this out though:
http://www.imdb.com/title/tt0464037/