There is a service on the net for bloggers that lets you post your GPS coordinates in your blog and submit it. Then people can surf for weblogs geographically. Does anyone recall what thats called?

Does anyone know of any open source, free, or reasonably priced mapping software solutions for the server side? Basically something that will let me put a dot on a map at a particular Lattitude/Longitude and then display the map on a web page?