As far as i know iPhone screen resolution is exactly same as the OCS/ECS amiga resolution. This smiplifiey Amiga game porting. No need to redraw or optimize graphics.
Actually, it's not the same (the iPhone has a 320x480 resolution). But in portrait-mode the width is the same and conveniently leaves room for additional controllers on the bottom of the screen, so it does make porting old games (not just Amiga, but also other machines like C64 and ST) a lot easier.
