http://www.wheresmyride.com.au/login.html
I believe this website is run by a dude in the ACT section here, as he had a chat to me about it not that long ago.
More or less, I can't remember the cost of the parts is about $150, he'll help you install the basics if you're in ACT, and then you just need a data SIM....the best value for money one available is through Vodafone, but it's $150 for 12GB that doesn't expire for a year....massive overkill, but unfortunately there isn't any other alternatives (at least when I was speaking to him, may be now)
There's also optional fuel-cut and in-cabin microphone, but he's never bothered with those himself. Otherwise, it updates location every 15 seconds, and you can view location and travel statistics via the website. VERY good imo, just a little on the expensive side to have running.