To be honest, I haven't tried this much. I just recently discovered it from http://bloggerindraft.blogspot.com/2008/12/new-feature-geotagging.html.
But once I tried to 'geotag' my post...but the load time of this feature sure is too long. It loads the map and puts strain to your connection. Then again, maybe I still don't know the proper way to use it... heheh.
Just drop a line here if you find it useful and tell me what you used it for.