Jessica is using a geo tagging feature.
Learn more about free open source geo tagging here http://geotag.sourceforge.net/
Also you can try Google's geo gadgets for your website.
http://www.google.com/ig/directory?synd=open&hl=en&gl=en&url=http%3A%2F%2Fmapbuilder.net%2Fgadgets%2Fgeodeveloper%2F1.0%2Fgeodeveloper.xml
Have fun.