I installed one of the Jaycar GPS trackers today and I've got to say for the price I am very happy with it. Once you work your way past the Jinglish the system seems to work very well!
Hi Adam, I was just having a look at the GPS tracker and noticed that it only operates on the 2G network, if you have a highway only policy for it you will be fine but as soon as it gets away from the major regional centres you will have issues. http://www.telstra.com.au/mobile-phones/coverage-networks/our-coverage/ and select 2G and you will see what I mean.
Mind you it would be interesting to use the engine kill switch function to activate the brakes once the vehicle has stopped, could be ugly doing it while the van was still moving.
I got one exactly the same in the wake board boat. The website it uses is a bit average, but buy sending sms text requests to the device, you get a reply with a web link using a similar map to google maps which shows the where about of you item.