Gran Turismo 5's release date is becoming a bit of a saga, with prospective western release dates coming and going, and in the case of Japan, actual release dates coming and going.
However, Sony are adamant this time that it will definitely be out in 2010 and according to the European PlayStation Blog, gamers should expect a concrete announcement about it soon.
SCEE's European Brand Manager, Penrose Tackie, said in a comment on the Blog, "I completely understand that you guys are looking for a date [for Gran Turismo 5]. Please bear with us, we will be making an announcement on that soon."
Source: PlayStation Blog