A free online resource with informational videos teaching a wide variety of topics for all grades.
Internet Public Library - http://www.ipl.org
This public library for the internet community includes special collections for kids and teens.
Yahoo Kids - http://kids.yahoo.com
A directory of internet sites for kids. Listed sites are checked to ensure content and links are appropriate for kids aged 7-12. The site also includes fun games, movies, news pages, a reference section, and much more.
Answers.com - http://www.answers.com
"Answers.com marries the best of community-driven questions and answers with hundreds of respected and trusted editorial reference books. The site knows the best answer to give you, whether it summons the expansive, ever-growing collection of community answers from WikiAnswers, or it taps into its ReferenceAnswers database, a comprehensive set of editorial, licensed reference topics."
The Khan Academy - http://www.khanacademy.org
Offers thousands of online videos teaching mathematics, science, history and more.