A resource which plots backbone servers and major datacenters on a geographical map would be especially helpful. The only two half-decent (emphasis on 'half') resources we've found so far are:

http://www.colotraq.com http://www.datacentermap.com

It would be nice if there was a Google Maps mashup or something better than DataCenterMap, but apparently that is (was?) considered a part of our nation's obscurity plan: http://www.washingtonpost.com/ac2/wp-dyn/A23689-2003Jul7