If you're looking for an app to combine checkins for Foursquare and Facebook Places try Checkin+ from the makers of IM+, a multi-protocol IM tool. Checkin+ will do just that, and adds the ability to see locations in a 2D map or 3D augmented reality view.
Checkin+ will also allow you to see friends nearby, which is fun for when you were supposed to meet somewhere, but you can't quite remember where. While I'd like to see a few more services supported (like Gowalla, especially), Checkin+ looks like a simple app that does something rather well. Check it out in action below.
