If, like me, you have been tagging your pics with location data for a while (a practice called Geotagging), then you will be happy to learn that Flickr recently released a new geotagging feature allowing you to place all your pics onto a world map.
However, the location data of my pics is embedded in their EXIF tags by the mobile phone I use to take the pics and the new feature doesn't read them from there, in the case of pictures added to Flickr before this new feature was released.
Thankfully, Sam Judson has released GeoReTagr, a little script that will import geotagged pics' EXIF data into the new location fields that Flickr uses to place the pics onto the map.
Thank you Sam!!
Here are my geomapped pictures on an UGLY Yahoo map!

UPDATE:
aemkei has released a delicious little bookmarklet that lets you tag any pic onto the nicer Google maps, from within any of your flick photo pages, without the need of an external script or application etc... (and it works with most browsers) and it also lets any person view your pics mapped on a nice Google map when they visit you Flickr pages or even as a standalone version:
here are my geomapped pictures on Google Maps with a delicious interface!