Ponk Room Maps
A quick look at the Leaflet map system - very useful
So this is the map produced by the Leaflet system. The whole system is Open Source and uses map data from OpenStreetMap. The copyright conditions are here. You can join in and help the development, or you can just enjoy using the maps. No magic numbers or other type of restrictions. Harry Wood has a lot more information and examples of use on his website
By its' very nature, most of the mapping is of the United Kingdom and Europe. The "Land of the Free" has some major towns marked but not much else.
The quality of the map is outstanding I think. It's easy to use and the documentation is good. You can set up clickable points which could be used to show your own photographs of a particular location.