A company called "iEmulator" is currently in the process of developing a Windows emulator for the iPhone. That should definitely be pretty interesting. If you've never heard of them before, they currently have a Windows emulator available for OS X, so they obviously know their ****.
It should be available in the second quarter of this year! Should be interesting trying to play Windows games on the iPhone (if the emulator supports 3D rendering, OpenGL, DirectX, etc.), which is currently underclocked to about 65% of its' full speed (to save battery life). The Asus EEE PC is potentially slower than the iPhone (believe it or not), yet can run games like WoW and Half-Life 2 really decently.