found this online for future reference
Since the time of its launch in June 2007, Apple’s iPhone has created a sensation in the mobile world. I think everyone out there has a secret desire of owning an iPhone be it for its superior touch-screen, or its motion sensing gaming or its extraordinary audio/video capabilities.
The iPhone has evolved from being just an expensive phone to an icon, a symbol of power. Imagine having to lose that.
Fear not iPhone owners. There are more than one ways of keeping track of your iPhone. A number of iPhone apps for tracking are available in the market. The good news is that some of them are FREE!! All you need is to enable GPS on your phone and of course a computer.
Ways to Find Lost iPhone
The first method is the ever reliable Google Latitude. Simply download and install the Google Latitude application on your iPhone and then create an id in Google. Once your phone has been Latitude enable, you can log in to iGoogle and view the location of your iPhone on the detailed Google maps. This app can help find lost iPhones in a jiffy.You can even enter the phone numbers of your friends’ mobiles and once they confirm it on their phones, their positions will also be visible on the map. Cool or what?
Another very useful and free GPS tracker is the InstaMapper. This cell phone tracker uses the same principle, which is GPS, for keeping track of your iPhone. To enable this on your phone you need to create a free account here. You need to enable GPS services on your iPhone to get this working. Also remember that Apple does not let 3rd party apps to run in the background. So GPS tracking will be turned off once the Home key is pressed.
I would strongly recommend you to check this guide to recover lost Apple iPhone and read the comments that provide useful insight on how to track lost iPhone 3G or 3GS.
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also your iphone has a "lost data" enable key. Under phone lock settings. Enable it. Simply means all the data on your phone will be lost after 10 attempts. Great way of protecting your personal stuff.