You can read the official release notes here.
However I know that what most of you reading this want to know is: Does it support PC graphics cards?
Well, the good news is it should support Nvidia GTX 500 and GTX 600 series cards as well as the new K series Quadros and it should also support AMD's radeon 7000 series cards.
The bad news is that I'm travelling at the moment so I won't have a chance to install it on my Mac Pro with a GTX 660ti for a couple of weeks :-(
I would ask any of you who have a PC card and do the upgrade to let me know in the comments so at least others can see what cards are working.
Thanks very much and I look forward to reading your comments.