Although the claim of a beyond retina definition screen is a bit of a stretch, this is still one impressive display on such a small phone.
At 326 pixels per inch, the pixel density of the iPhone 4 is four times that of the iPhone 3. Jobs claimed at the conference that the resolution surpassed that of the unaided human eye, which cannot differentiate detail past 300 pixels per inch; Wired revealed later, however, that this claim was false.
via Mashable