Other
Alien Travel Guide: Elements of Music the Basics
Fine site created for Canadian schools devoted to basic elements of music, including pitch, acoustics, time signatures, keys, and rhythm.
Quia
Quia: Musical Elements
A great matching game to reinforce music vocabulary and an understanding of the elements of music.
University of Illinois
University of Illinois Urbana Champaign: Learning Musical Elements Through Listening
This is a site created for teaching children the art of listening to music. Includes sections on the elements of music, composers, and genres with more under construction.