Today, the location-based social networking site Gowalla launched version 3.0 of its app for the iPhone (an Android version is coming in 2011), which adds unified check-ins with Foursquare and Facebook Places to the mix. The app also supports sharing on Twitter and Tumblr.
To test it out, we downloaded the app on our iPhone 3GS, entered our account information for Facebook, Foursquare, Tumblr, and Twitter, and promptly checked in to Times Square. Within seconds, the check-in registered on each of the four sites. Presto!
In addition to offering unified check-ins across four social networks, Gowalla 3.0 also boasts a Notes feature, which lets you leave messages for your friends at a certain check-in location. (Once your friend checks in, they'll be able to see your note.) There's even an "express" check-in feature, which speeds up the process by guessing where you are based on your history.
If you're a heavy social network user, definitely give this free app a whirl.