Geotagging
I’ve been geotagging my Sydney photos on Flickr using MultiMap, which gives you the longitude and latitude, and then add links to Google Maps satellite photos of the location. It’s either the location of the subject of the photo or the approximate point of view where the picture was taken. The pictures with satellite photo links can be found here, or just browse my Sydney collection and click the link when one’s included.
More about geotagging on Wikipedia.