iDeals China, a Chinese reseller of Apple parts, has published an image of the digitizer panel for the fifth generation iPhone's touchscreen. Although no measurements for the cutout were posted, it would appear that the next iPhone will still be roughly the same size as the current iPhone 4, but would simply squeeze in a larger screen into a thinner bezel (on all sides). This is assuming, of course, that this image is real; we're still classifying this as a very early leak.
The next iPhone will likely debut this summer. Specifically, we're expecting Apple to release its latest and greatest in June 2011.