Thanks to Donato Rumi at VPN Americas I have transformed data that he sent into a map of US VPN-certified businesses. (VPN Americas is the official delegation for USA and Canada to Associazione Verace Pizza Napoletana, hence the abbreviation VPN.)
His web page VPN certification, is likely to be kept more up to date. (We are going to work on keeping the versions coordinated; the current revision date of the map is 07/11/12.)
If you are fond of authentic Neapolitan wood-fired pizza, you can use this map to locate your nearest VPN-certified restaurant.
The map now supports links to each business that has one, as well as their phone numbers. (There is a small symbol *outside* the upper right-hand corner of the map that will make the list of businesses appear and disappear.)