Printmaking

What is a print?
http://www.moma.org/whatisaprint/
Museum of Modern Art's site has a clearly illustrated explainations of woodcut, etching, lithography and screenprint. It is also fantastic example of using Flash to educate.

International Mezzotint Society
http://www.math.ufl.edu/~glover/mezzotint.html

Graphic Chemical and Ink
http://www.graphicchemical.com/
For the reputation of this printmaking supply company, their site should be better designed, but they spend their time making quality inks, not web pages.

Spencer Museum of Art's Image Maps of Printmaking Techniques
http://www.ku.edu/~sma/techmap/techmap.htm
This University of Kansas museum built a straightforward reference of printmaking techniques described and demonstrated with works from their collection. Image maps allow you to zoom in on the details and get as up close and personal with a print as you can get in cyberspace. And here's their glossary and printmaking homepage.