Recommended Links
Khan Academy (online videos)
An introduction to chemistry (free book online)
Periodic table of the videos.
Join the American Chemical Society!
Online quizzes in general chemistry.
The orbitron, a gallery of atomic orbitals. (Check out those g-orbitals! Freaky...)

Chemistry worksheets: Hone your skills practicing balancing equations, stoichiometry calculations, molarity examples, oxidation numbers, etc.

Interesting stuff!
What if you had a mole of moles?

Mnemonic for the SI prefixes: