I thought I had lost my phone for the past day, I looked every where and called it a few times, no luck. So I remembered I had the InstaMapper GPS software installed. You can send an SMS to the phone with your InstaMapper key to activate the GPS and have it report its location. Worked perfectly, apparently the phone is at my house some place hanging out without me, nice. I think its pretty cool that you can activate applications this way with the G1 phone.
Since iPhones don’t allow applications to run in the background, it wouldn’t have been possible, just another lost phone ringing with nobody to hear its plea to be found. I recommend anyone with a G1 to use InstaMapper. I also created an AIR application that tracks your device with Google Maps.