Developing for iPhone 5 screen resolution isn’t very obvious and there is (for now) no good official documentation about how to be compatible with the new 1136×640 size.
There are a few steps to take before you are iPhone 5 compatible. First Download and install Xcode 4.5. Set a 4-inch launch image for your app. To adapt your app to the new taller screen, add the launch image to: Defaultfirstname.lastname@example.org. Now your app will run in full size and you will have to test if all your views will adjust correctly, so go and adjust your views with proper auto resizing masks or take a look at the Auto Layout.
It’s worth noting that [UIImage imageNamed:@”background.png”] will still only load either “background.png” or “email@example.com”, it will not load “firstname.lastname@example.org” if it exists!