Google Maps with GPS Tracker shows your physical position in real-time on a moving Google Map. A small application on your PC uploads your GPS position periodically over either GPRS or 3G, which updates your position on a moving Google Map.
Don't worry about having a GPS device, you can using GpsGate (gps simulator, 14 day trial). Then later you purchase fancy gps devices. You can connect to the internet anywhere via pc (pc + GPRSmodem + sim-card)