The add-on available for several cameras is a clever solution, GeoTate, for tagging images that doesn't drain the camera battery. Instead of carrying a full GPS chip, the camera uses GPS radio and captures just base information and the actual location is determine by communication with servers after the images are downloaded to a computer. The solution was launched at PMA (the photo show) in Vegas this passed week.
Per engadget, the cameras inlcude a "GPS radio courtesy of New Zealand-based Rakon." Here's how GeoTate works:

every time the shutter is triggered, the camera's memory card briefly captures the raw data from the GPS radio, associating it with each photo. Then, once the pictures have been imported into Geotate's proprietary client, auxiliary location data is downloaded from a central server, which is then synthesized with the camera data using local resources to establish actual coordinates.