The Bathroom Diaries is a website that allows you to search for a public restroom in the country, city, and state of your choosing. The site also tells you the whether the bathroom is clean, handicap accessible, and if it is safe. You can also check to see if there is a changing room or if the restroom is aesthetically pleasing.
Don't forget to check out the awards page. The site currently features the public bathrooms in the center of Kawakawaka, Bay of Islands, New Zealand as the winner.