Open Virginia Data Toolkit - collection of tools, resource, references and sources for interacting with data in the commonwealth of Virginia.
Geojson - world.geo.json
https://github.com/johan/world.geo.json
Geonames
http://geonames.org/
Gazetteer Data - GeoNames.org
http://download.geonames.org/export/dump/
http://download.geonames.org/export/dump/US.zip
Postal Codes - GeoNames.org
http://download.geonames.org/export/zip/
http://download.geonames.org/export/zip/US.zip