Google Maps My Location uses either GPS (if it's available on your phone) or triangulation from the closest towers to show where you are. And yes, it works in Australia.
But it's not as impressive as I first thought. When I tried it initially in the Melbourne CBD (where there are
lots of towers) on my non-GPS-capable Nokia 6230i, it showed the map and pinpointed to within a few hundred metres of where I was at the time, pointing roughly to the corner of Swanston Street and Flinders Lane. Wow!
Alas it turns out that it points to that location wherever I am in greater Melbourne. Oh dear.
Still, at least it got the right city and continent. That's a start.