Make that the "theoretically new iPhone screen size". But still, it's a nice hack from Cedric Luthi.

Earlier today, my friend Peter Steinberger asked if there is a way to tweak the iOS simulator device size. So I investigated, and found a pretty elegant solution. Without further ado, here is how to change the size of the iOS simulator in order to test your apps in resolutions never seen before.
You are now ready to test your apps on the rumored 640x1136 new iPhone.