Since the wage data is publicly available, does anyone know how I would go about replicating these maps? I know I could use Google's charting API's for County/US state level, but how would I go about mapping data at the US county level?
You can download the bounds of each US county (and many other political subdivisions) as shapefiles from the Census TIGER/Line repository. http://www.census.gov/geo/www/tiger/
Just always wondered how that would work :)