Will Smith has committed to Men in Black III (in 3D) and Sony / Columbia have set the film for release on May 25, 2012.
Men in Black 3 is officially a go, and Columbia Pictures will set a May 25, 2012, release date for a sequel that director Barry Sonnenfeld will shoot in 3D. Will Smith has signed his deal to reunite with director Barry Sonnenfeld, and deals are now being negotiated with Tommy Lee Jones and Josh Brolin. An announcement is imminent.
Source: Deadline