A new “Map” button in the Organize tool and a new “Map” button on everyone's Flickr page results in pretty easy access to the functionality.
I've geotagged a few recent sets - you can check out the resultant map on my Flickr page.
So, what does this mean? Well, for a start, a lot of people are going to now start geotagging their images, which means that you'll be able to search for images by location and there will actually be some results. Image location search just hasn't been interesting before as there really hasn't been any data.
Expect to see a lot of location based image mashups appearing very soon…