Here are some great WWW sites (in no particular order):

Miami Museum of Science
U.S. Holocaust Memorial Museum - great resource for teaching the Holocaust
Holocaust Pictures Exhibition - some pretty heavy-duty pictures of the Holocaust
CNN
Time-Warner's Pathfinder - Time magazine, People, Entertainment Weekly, etc.
Vocabulary.com
Mpls Inst Arts - Education - Minneapolis Institute of the Arts
Researchpaper.com
Pitsco's Ask an Expert: Categories - Have a technical question? Ask an expert!
InTech 2000 Forum
Teaching Ideas and Topics
Teachers' Resources - Literature
Jane Austen Info Page - one of my favorite authors!
Witches - a resource if you're teaching The Crucible
Salem, Massachusetts - Welcome - same as above
History of American Literature
USIA - Outline of American Literature - Contents
DCPS - Dade County Public Schools

Yet More Stuff