As most people who read this blog are probably aware, Flickr added mapping directly. What they didn't advertise or get talked about is the formatting they're supporting.
Hidden underneath the "taken..." line is a bit of Microformat geo:
Additionally, in the RSS output, you can get GeoRSS tags. You need to add the following to your URL: &georss=1.
It's a great example, and source, of how easy it is to add some simple markup to your HTML and RSS to add geographic annotation.