MAKE: DIY GPS tracking
"DIY GPS tracking with 'disposable' phones - Mod a GPS enabled Nextel and fauxjack yourself...or your car, or your kid, or a big dog, or an elephant. We really, really want to track an elephant. Mologogo is a free service that will track a 'friends' GPS enabled cell phone from another phone(gps not required) or on the web. It currently works on pretty much any Nextel phone with Java and GPS - even a $60 no-contract Boost Mobile phone."