There should be an image here!Millions of people are checking in with Facebook Places, Gowalla, and Foursquare, but do consumers understand the intricacies of geo-location services? Checked-In: How to Use Gowalla, Foursquare and Other Geo-Location Applications for Fun and Profit, is the world’s first published book on location-based mobile applications.

Geo-location services are mobile applications that allow users to share their physical whereabouts with their networks. The book is filled with useful and easy to follow information, covers how players in the game will change the landscape, and how you can stay ahead of that curve. Checked-In, published by Herb Tabin and Craig Agranoff, shows users how to get the most of these free and powerful location-based mobile applications.