This application runs an OS 9 Mac Emulator on your iPhone. So now you can have those good old days Mac application back on the IPhone (MacPaint here we come ).
This emulator is based on MiniVMac.
I don't known if its usefull but it shows at least the capabilities of the IPhone.
Note: the only caveat there is , is that you need a Mac Plus ROM image, and where on earth do you get that ?