Just before (I think) the map search engines started including satellite pictures in their sites, Google Earth came out. You have to download an engine to run it. (and remember: double-clicking on the plus or minus sign zooms in or out as long as you don't click again, so it can be frustrating if you're not sure what the heck it is doing)
Anyway, I was just prompted to reload the engine yesterday (I'd loaded it when it was new, but the hard drive died and I had to get a new one, etc, etc) when Wikipedia showed me that it has a Google Earth link for a town that I was curious to know about (actually, curious to know if there was any more info that I didn't already know about it - it's a small place).
Well, as coincidences show, there is an interesting article I just found today. It talks about how scientific research is being doing on Google Earth. Pretty cool.
Google Earth Embraced by Geologists