All of these resources provide an excellent overview of general reference material.
International Children's Digital Library
A digital library of international books for all children
DK Find Out!
Check out the beautiful images and clever way they have presented the information.
Ask the Experts
Awesome Library - K-12 Education Directory
Facts Subject Index - Refdesk
Provides 24 resources for reference categories.
How Stuff Works
Describes the composition, function and appearance of hundreds of items.
Internet Public Library
A great online library reference
A great way to find both fun stuff and information for completing your homework assignments.
LibrarySpot - a virtual library resource center