The Library of Congress. You will find copyright information and photos. There are vast collections of historial pictures and films and sounds.
http://www.loc.gov/ 

Here are some encyclopedic references
http://www.encyclopedia.com/

Dictionary, thesaurus...help with words
http://www.voycabulary.com/

Here are answers, answers, answers...
http://www.whatis.com

Look! Bad Stuff! A collection of badly designed things in our world...and why. It is enlightening.
http://www.baddesigns.com/index.shtml

The Yale Web Style Guide. This is a good guide to the design of web pages and is relevant to interactive design and print. The strategy of design is great.
http://info.med.yale.edu/caim/manual/