This is a "new-to-me" interactive exhibit from the Smithsonian.
Those of you studying James McNeill Whistler may want to take a look:
http://www.asia.si.edu/exhibitions/online/whistler/whistlerdefault.htm
(requires Flash)
It is particularly good for those of you doing drypoint/etching prints
-many good examples for students to see techniques.
Exhibit is organized by medium, genre and place (warning- it does have nudes).