Now Harvard University is also offering free online courses. Each class is a series of online videos. You will not receive course credits for completing them.

Intensive Introduction to Computer Science for free
The Heroic and the Anti-Heroic in Classical Greek Civilization for free
Bits: The Computer Science of Digital Information for free
Shakespeare After All for free
China: Traditions and Transformations for free
World War and Society in the Twentieth Century: World War II for free
Sets, Counting, and Probability for free
Abstract Algebra for free