The Google Maps system is on permanent display on Daden Prime in SL. However, if you don't have Second Life, thanks to the wonderful Digital Urban you can get an idea of what Daden Ltd have achieved through this amazing video.
Coincidently you can also view David Rumsey's historical map collection in Second Life by visiting the David Rumsey Maps Island (this is a link that will open Second Life). Personally I prefer to view the David Rumsey Historical Map Collection on Google Maps.
Via: Digital Urban