I have a zoombak on my vehicle, cost $99 plus a $15 monthly fee. It lets me monitor when vehicle leaves a "zone" (A defined distance from a defined lat/lon point) it sends email and text messages when the zone is entered or left. I can have many zones. I can also query where my vehicle is at any time from iphone or any browser. it also lets you look at the track the vehicle has taken.
I got this after my vehicle was stolen 2 times in less than one year. If they steal it now I will be able to track where it is and fine it myself. Cops were useless in locating vehicle.