Ars, on the development of Besiegement (iTunes Link), a tower defense game for the iPhone, made (mostly) on a PC:
The PC development side consisted of two OpenGL windows representing landscape and portrait views. These windows translated mouse movements into “touches,” similar to fingers. The right mouse button simulated a second finger, similar to the iPhone simulator on the Mac. In addition to touches, Randall added keystroke equivalents for standard system events including the Home button press, the lock button, low memory conditions, incoming calls and so forth. He used a pop-up dialog to stand in for the iPhone’s keyboard, and added other placeholders to represent iPhone UI elements. In the end, he not only matched the Simulator’s event suite, but built upon it to add events that Mac-based developers would love to see included.