PBS accompanying site for the “Great War” video series
BBC on the 80th Anniversary of WWI
Mt. Holyoke’s extensive collection of primary sources
Georgetown University’s collection of US Propaganda Posters
firstworldwar.com (note: the author of this site, Micheal Duffy, full concedes that his is an amateur site– but is it a fine one)
Songs of WWI (almost all songs from the US)