I believe they are using (http://google-maps-utility-library-v3.googlecode.com/svn/trunk/markerclusterer/examples/simple_example.html http://google-maps-utility

I believe they are using (http://google-maps-utility-library-v3.googlecode.com/svn/trunk/markerclusterer/examples/simple_example.html http://google-maps-utility-library-v3.googlecode.com/svn/tru...)