It seems that PSP owners will have to wait even longer for Gran Turismo to hit the portable scene. A PSP version of Gran Turismo 4 was planned for the handheld's launch in 2005 and now it is looking to be released during 2009.
Series creator Kazunori Yamauchi has stated that, although he's working very hard on Gran Turismo Portable, the game won't be released until Gran Turismo 5 releases.
Currently, Yamauchi has Gran Turismo 5 set for a Holiday 2008 release, but that is still in question. Yamauchi has no intentions of releasing the game until everything is perfected.
With the release date of Gran Turismo 5 planned for a late 2008 release in Japan, the PSP version will likely come to light sometime in 2009.