Gnome wrote:*off topic*
he probably just took a real world map or a map of the US, took his brush on 3px and went around the borders...than filled it with the brown colour and done...if you want to know more about photoshop or other problems we have a thread 'map making tools' and you can search for some photoshop tutorials along google...
Among a few various effects, and a 2 px brush, but yeah basically.