Thought I'd post up a couple links for those interested in vehicle tracking hardware/software.
These two are at the mercy of cell phone coverage. They report the current location of the vehicle by GPS but the software works by calling you by cell phone. You have to pay for cell phone service/monitoring. The good thing is that it increases chances of recovering a stolen vehicle plus you can track your children if they're driving your vehicle or one the hardware is installed in.
GPS-Snitch | Home best price I've seen on it GPS Snitch - 001
AccuTracking - Online Real-Time GPS Phone Tracking Service
Car GPS Tracking – GPS Car Tracker Systems and Devices - Descriptions and Pricing
GPS-Car-Track GPS Vehicle Tracking and Recovery