Stephen Shankland's written a really nice overview of geotagging, looking at the tech available for those who wish to add geographic tags into the digital photography mix.
"Today, geotagging is not for the faint of heart. It requires a Global Positioning System (GPS) receiver and either software that adds GPS data to photo files or an expensive camera that communicates directly with the GPS device. But as the technology takes off and sites such as Yahoo's Flickr or Google's Panoramio show off the possibilities, the elements of geotagging are starting to come together."
CNET also has a photo gallery which shows off geotagging technology on Flickr and Google, as well as some geotagging-friendly cameras.