According to SuperPhone.cz, the next iPhone has been confirmed to have a 960 x 640 resolution display. The site claims to have obtained iPhone displays that were floating around and put them under magnification.
The technique they used where counting the RGB elements on the display, and they found that the display was exactly twice as dense as the current iPhone's display.
It has been rumored for some time now that the next iPhone would sport a much higher resolution display.

