When does Gears Of War 3 come out

Gears of war 3 official release date is in September 2011 and here is a website http://gearsofwar.xbox.com/?uid=109105148&tid=358 and it contains the month and year it comes out and a trailer
Gears of War 3 is slated for release on the Xbox 360 on September 20, 2011.