What is Gowalla?
http://gowalla.com
Gowalla is a location based social network that encourages you to go out into the world and share your experiences. You may have heard of, or even use, one of Gowalla's competitors but you don't have to pick favorites anymore. Gowalla let's you check-in on Foursquare, Facebook, Twitter and Tumblr all at the same time. Plus, Gowalla has one of the most beautiful interfaces and is incredibly user friendly.
Facebook: / gowalla
Twitter: / gowalla