Euro Trip! Foursquare Invades Europe.

Foursquare has a lot of momentum in the location-based social networking space right now but one thing holding it back is that’s it’s largely a U.S.-only phenomenon at the moment. This isn’t surprising considering that Foursquare works in all of five cities outside of the U.S. (three of which are in Canada). But that changes today.

Foursquare is rolling out its service in 15 European cities today....