Was it really only last June that Apple introduced the Find My iPhone feature? Since then it's stopped thieves and more than paid for itself. Now there's an iPhone app (for installing on iPhones other than your own, obviously).
It's been added to the App Store just today for iOS 3.1.3 and higher products, and is free (though you will need to have a MobileMe account, which costs $99 each year—or check out the free 60 day trial). The idea is to strike a deal with friends/family who have iPhones/iPads/iPod Touches, so if yours is lost or stolen they can then use their Apple device to find yours. Capiche?
You can also remotely lock your lost Apple gizmo using their app, or even delete all the data if it's beginning to look like a lost cause. After 15 minutes of inactivity, the app signs your log-in details out, ready and waiting for the next friend who drunkenly loses their iPhone in a cab. [iTunes via Engadget]