Forget the controversy surrounding Apple's claims about the iPhone 4's Retina display. I'm more interested by these folks at Penn State University who decided to grab a microscope, an iPhone 4, an iPhone 3G, and start counting pixels.
Those folks, PhD candidates Ryan White and Bryan Gauntt, found that "the iPhone 3G's pixels measure 13 x 40 microns, while the iPhone 4's measure 6.5 x 20 microns, which adds up to exactly four times as many pixels." Nothing shocking, but you can check out more comparison pictures from their mini research project over at Engadget anyway. [Engadget]