John Gruber speculating the next iPhone screens:

But after giving it much thought, and a lot of tinkering in a spreadsheet, here is what I think Apple is going to do:

• 4.7-inch display: 1334 × 750, 326 PPI @2x
• 5.5-inch display: 2208 × 1242, 461 PPI @3x

@2x means the same “double” retina resolution that we’ve seen on all iOS devices with retina displays to date, where each virtual point in the user interface is represented by two physical pixels on the display in each dimension, horizontally and vertical. @3x means a new “triple” retina resolution, where each user interface point is represented by three display pixels. A single @2x point is a 2 × 2 square of 4 pixels; an @3x point is a 3 × 3 square of 9 pixels.

It’s lengthy but if you geek out on this kind of thing, it’s worth the read.