I am on developing my own location-tracker Programm.
See
www.car-pc.info/carsoft/ -> Position
It works on my car-pc with a internet Server running (WAMP)
I get the gps data from my GPS Mouse and a Nav-Programm thats login my nmea datas.
I read it with a php programm and store it in a mysql-database.
there you can afterwards get your tracking datas for further use.
Also the PHP Prgramm sends on time to time (adjust.) my positon via GPRS or WLAN to my Internet Server. There anyone can see my position. Of course it could be locked for spec. users.