iPhoneShopper.com

Apple made this "Find My iPhone" functionality available with the release of iOS 4.2 and even allow you to register for a free MobileMe account to be able to track your phone from any web browser. With your new MobileMe account you can now logon to www.me.com and start tracking where your iphone currently is on a map, remotely wipe your data etc.

Further to this Apple created a "Find My iPhone" Appstore App, again free of charge, so you can track your idevices (iPhone/iPad/iTouch) from another idevice if you had one handy at the time.

So the real question is why haven't you already set this up - don't waste another moment, head to the following link for instructions to do so.

http://www.apple.com/iphone/find-my-iphone-setup/