Google Maps Streetview
One of my favourite sites cataloguing Google Maps streetviews is about to hit the deadpool unless someone volunteers to take it over. The creator of Streetviewr says he doesn't have the time to run the site any longer so I would check out the site quickly before it disappears into the ether.
Alternatively if you are interested in taking over a superb website then contact Streetviewr with your interest.
Our much, much smaller streetview directory is available here.