Stalqer, available as a free iPhone app since earlier this month, has solved this problem by connecting to your Facebook, Twitter and Foursquare accounts and providing a map of your friends based on information it gathers from those services, even if they don’t use Stalqer.
If your friend uses a geo-tagged Tweet, or if they check in on Foursquare, Stalqer knows where they are. Stalqer can even pull your friends’ location from their Facebook profiles if they publicly display that information, but in most cases this is limited to the city level.
You can also view your friends’ locations in a list, or even in an augmented reality view by turning the phone on its side while in the map view, but Stalqer’s killer feature is its workaround of a pesky iPhone limitation.
