Funny you should mention that game here. It was orginally expected in 2002 i believe and when it did eventually get released in 2005 it got slated pretty badly by critics. Lets hope GT5 wont be subject to a similar fateI think it was "Driv3r" where they released the guide a few weeks earlier than the actual game.
Just saying, don't build up false hopes. Wait for an official date on a Sony site.
Although one good thing i randomly got sent the game 10 days early