According to IMDb, the U.S. release date for A Serbian Film is May 13, 2011.

Yes, that's Friday the 13th.

Update 03/03/11: the film's distributor, Invincible, has confirmed the release and has started a Facebook and Twitter campign to promote the film. There will be a free preview of the unedited version on March 10th at the Prince Music theater in Philly.