The site says the MSRP at launch will be $649 for the GeForce GTX 280 and $399 for the GeForce GTX 260.
The web will be flooded with reviews once the press NDA expires on Monday, June 16th at 6:00 AM PDT and the GeForce GTX 280 will be available in volume on Tuesday. Unfortunately you'll have to wait until Thursday, June 26th to get your hands on a GeForce GTX 260.
In the weeks after the launch of these and AMD's new graphics cards you can probably expect some price cuts, word is going around that the GeForce GTX 260 may quickly drop $50 but I wouldn't count on a price war as AMD can't afford this if they want to get back in the green this year.