Homeschool Skedtrack Best Sites -- World's Top Educational Websites

Project Gutenberg, PG, is the oldest digital library. As of December 2007, PG claimed over 27,000 items in its collection, with an average of over fifty new e-books being added each week. These are primarily works of literature such as novels, poetry, short stories from the Western cultural tradition. PG also has cookbooks, reference works and periodicals. (From Wikipedia)

From their website:"The Online Teacher Resource". A ton of free stuff for school.

Great Science resource for students K-12 even older students. Offering stories to read, facts tied to pictures, images, videos, online educational games,  contest/competition information, NASA World Book - great for research, and a lot more!

Latin is a rich, ancient language, and is still very much alive in the languages that we speak today. It plays a vital role in a classical education, training students in grammar, how a language works, and how to think critically. Learning Latin greatly expands English vocabulary and introduces students to the original work of some of the most influential writers in history. 

Online World History resource - this site starts with the "Big Bang" Theory ... A good secular (not Christian) World History resource.

On this site, you will find resources to help students master the basics of mathematics of numbers and number operations. Videos and tutorials explain basic operations and help with the mastery of math skills in addition, subtraction, multiplication, and division--essential building blocks for success in mathematics.

KidsAstronomy.com is an absolutely free astronomy resource designed to teach children about the exciting world of outer space. This astronomy website is packed with games, activities, fun facts, and resources to help Teachers, Parents, and Students of all ages reach out and touch our universe.

A unique collection of thousands of videos, images and fact-files illustrating the world's species.

"Math Worksheets World. Math Made Easy! Math Worksheets World is every K–12 teacher, homeschooler, and students´ dream come true!" - A really good math site. I used it this year.