Hard wire the phone charger and hide it and the phone and if you rig/whatever come sup missing just call the phone and you know its where abouts

text from site

DIY GPS tracking with Mologogo - review
Earlier, we posted about the DIY cheap GPS tracking service Mologogo, you can get a cheap $60 pre-paid boost mobile phone, register on the site, download a Java app and you're pretty much done. The phone will transmit your position to server (Uses Rails, Linux, Google Maps) and you/your friends can view where you are at in real time. I've hacked up tons of solutions to do the same thing, and this is simplest and cheapest (pretty much free if you have the phone, or $60 if you go pre-paid + 0.20 / day).






http://blog.makezine.com/archive/200..._mologogo.html