4Teachers A great site for many different resources!
United Streaming
FunBrain
Web quests:
http://www.webquest.sdsu.edu
http://www.webquest.org/index.php
http://www.techtrekers.com/webquests/
http://school.discoveryeducation.com/schrockguide/webquest/webquest.html
Voicethread
Filamentaly
Dozens of teacher links for everything from Jeopardy to PP presentations
Global Classroom hundreds of links
Interactive Websites