Gowalla, the check-in service that competed with Foursquare, has opted out of direct competition and has now released Gowalla 3.0 for iPhone (free, App Store) to let users link to their Foursquare and Facebook accounts. The app also lets users view their friends' check-ins from the three services. The user interface is also now slightly improved, with the check-in button accessible from the toolbar.
