I once did this for a facebook competition; An estate agent would post pictures and you had to guess the location.
After checking the landscape, scenery, road sign styles etc I managed to reverse engineer the exact streetview URL from the image.
Here's the image: http://i.imgur.com/lKeAXsE.png
And the streetview URL: http://maps.google.com/maps?f=q&source=s_q&hl=en&...
Turning it into a game is a stroke of genius. I can see myself wasting a lot of time on this!