There is
www.mologogo.com. It's free and works with Nextel/Boost Mobile, Windows Mobile, Blackberry devices, maybe more. I think it can be tracked using any browser or data capably phone. I don't know much about it, but a friend had installed it a few months ago and had me look at it. I was busy at the time and don't remember much about it, but it did work and seemed to track in real-time. I remember watching him drive down the freeway...