You Can Use Find My iPhone For Free On Older Devices
Apple claims only iPhone 4, iPad, or 4th generation iPod touch owners can use Find My iPhone for free by logging in with their Apple IDs. It turns out, though, that enabling support on older devices is fairly simple. Lifehacker reports:
Once you've activated Find My iPhone on a newer iOS device, just repeat the steps above on a pre-2010 iOS device and it should work like a charm. I tested the process by turning on Find My iPhone on an iPad, then enabling it on an iPhone 3G.
Piece of cake. Just borrow an "officially supported" device from a friend, log in with your credentials to activate the feature, then delete the account from your friend's device.