Via a Japanese press release, Sony has confirmed that it will be delayed by around a month, but hasn't announced a firm release date.
Polyphony Digital's Gran Turismo 5 features a brand new damage modeliing system and an exhaustive list of cars, including electric cars, such as the Honda Insight and Toyato Prius. Furthermore, approximately 170 vehicles will feature realisitc interior damage modeling. The rest of the roster will show external damage only.
It's believed that Polyphony Digital's hasn't been able to persuade some car manufacturers to let them virtually smash up their vehicles inside and out.
It promises to be a blast, when we do eventually get our hands on it.