Ha, here’s a desktop app to make an iPhone developer smile.

PhoneFinger adds a human finger to the iPhone simulator on your Mac. Instead of just watching mouse clicks, you get to see a correctly-scaled finger “touching” the elements of your app. There’s even a pref for it to leave realistic greasy finger smudges.

It’s useful for testing, yes, but also nice for making screencasts that demonstrate your app’s features. Here’s one for Aki Mahjong Mobile that shows the kind of effect you can get.

More amusing still, PhoneFinger does not require you to have the iPhone SDK installed. It works on any Mac running Leopard, in any application. Amuse your friends and confound your colleagues by installing it in secret, and see how they get on with it.