http://blog.us.playstation.com/2010/10/13/gran-turismo-5-release-update/
Well that sucks. Still coming out this year though. Will be updated when more info is available.
Update: the game apparently suffered a 3 day delay in going gold. How that translates to retail is currently uncertain although this should assuage any fears about it not releasing this year.
http://www.gtplanet.net/gt5-missed-production-window-by-only-3-days-sony-determines-new-dates/
Update #2: The delay in going gold was to reprogram it to run on firmware 3.5.
http://forum.blu-ray.com/blu-ray-games-playstation-3/101570-gran-turismo-5-delayed-108.html#post3872491