North America

CanHighways.com
Organized by state or province.
http://www.canhighways.com/

The Chris Kadlec Road Photos Gallery
Various views from trips around the continent.
http://www.beaglebass.com/roads/

Greg's Road Sign Pages
Wide coverage in the United States and Canada.
http://www.geocities.com/~wgrc/roadsigns/rmain.htm

Gribblenation.com
Includes information primarily covering the eastern third of the continent.
http://www.gribblenation.com/

Neil's Summer 2002 Roadtrip
Photo log of the Upper Midwest and Ontario, Canada.
http://nbratney.tripod.com/vac-2002/

Roadfan.com
The Lincoln Highway, the National Road, eastern Canada, and the Lower Mississippi River, Great Lakes, and New England areas in the United States.
http://www.roadfan.com/

State Line Signs
Includes personally-taken examples from both U.S. states and Canadian provinces.
http://www.johnweeks.com/stuff/states.html

State Route Salute
State and province route marker gallery.
http://www.angelfire.com/ne/msittel/Sroute.html

Why Do You Have So Many Pictures of Road Signs?
Includes U.S. and Canada coverage.
http://www.teresco.org/pics/signs/