Google Maps extension for Firefox
If you are in the US (sadly Google Maps only covers the US area) this looks like a very cool firefox extension!
“Google Maps Live is an extension for Firefox 1.0 that allows you to feed latitude/longitude data to Google Maps and have it tracked in realtime. The extension works by listening for the data on a socket.”
Now, if you have a GPS, it is nearly trivial to write a piece of perl to reformat the NMEA feed from your GPS on a serial port to the socket.. Or do some other fun stuff. If your photos had GPS coordinates (something we had in mind for F-Spot eventually) you could for example look up the locations while you do a slideshow on another computer..