The New York Public Library has been taking notes from goggle. They have made illuminated manuscripts, historical maps, vintage posters, rare prints and photographs, and illustrated books available for free online. Most seems to be in the public domain and the library is only asking for some sort of fee for high-resolution version of the images, though I can’t find out how much.
As a poor graphic artist new to the field I’m always happy to find new places to get stock photography. Hopefully this is a sign that this digitizing of the past is not just a trend and will really take off. The more power at the tip of my fingers the happier I am.