How do people make maps like this?

[flishess]

Look on this page, it looks like some kind of google map plugin or something:

http://www.darkfallunholywars.info/world-map/

I want to do something like this for my own custom created map, if anyone can point me in the right direction it would be greatly appreciated, thanks!

 

[Chicken]

They're using google maps but basically using custom tiles, you need to get familiar with google maps API and everything.

Something to start with would be this as a base, http://www.dicabrio.com/javascript/custom-world-google-maps.php