CheckinSpy lets you view your friends Facebook check-ins on Google Maps.
The application allows Facebook users to view their own check-ins and those made by their Facebook friends directly on a Google Map. You can select to view your own check-ins from the menu bar at the top of the map. Alternatively you can view all your friends or select an individual friend's check-ins.
All recent check-ins are displayed on the map with orange map markers. If you click on the marker you can view the date of the check-in and view the location with Street View.