http://www.filmmetro.com
http://www.gofobo.com
http://www.fatwallet.com/forums/free-stuff/742187/?start=1980 (message board)
http://www.wildaboutmovies.com (warning: has many pop-ups)
There are also Facebook and Yahoo groups devoted to movie screenings.
So stop staring at that computer screen and go stare at a movie screen!