http://ipodclassroom.wikispaces.com/ - iPod apps for all levels. 

http://siftables.com/ - The future of educational technology!  Coming soon! 

http://mystudiyo.com/ - Quizzes for your website or blog.

http://classtools.net/ - Create education games, diagrams, and activities in a Flash!

http://www.edutecher.net/index.php - Variety of edtech tools!

http://www.neok12.com/ - Educational videos for K-12 school kids.

http://www.thinkfinity.org/ - Variety of K-12 Lesson Plans.

Open Learning Initiative - Open and free online courses.

http://www.fieldtripearth.org/ - Global resources for proponents of wildlife conservation. 

http://copyrightfriendly.wikispaces.com/ - Copyright friendly sites for your blog, wiki, and more.

http://teacherlibrarianwiki.pbworks.com/Copyright+Friendly+Image+Sources - Copyright friendly images.

http://perkupprojects.wikispaces.com/Logos - Logo generators to perk up your wiki, website, blogs, and more!

http://www.eduplace.com/graphicorganizer/ - Printable graphic organizers.

History:

http://havefunwithhistory.com/ - Resource for American history.

http://www.footnote.com/ - Historical documents.

http://www.nbclearn.com/FINISHINGTHEDREAM - Free video series about the civil rights movement.

Math:

http://www.gamequarium.org/dir/Gamequarium/Math/ - Math games by topic.

National Library of Virtual Manipulatives - Virtual math manipulatives.

Music:

http://www.jamstudio.com/Studio/index.htm - Create music beats.

http://www.musipedia.org/ - Open music encyclopedia.

Science:

Chemistry Comes Alive - Interesting chemistry videos.

Art:

http://www.techlearning.com/blogs/31344 - Top ten sites for creating digital art.