Other
Dr. Brian Blood: Music Theory and History Online
An exhaustive resource with everything concerning music theory. From ear training to music history, this site covers it all.
Music Theory
Music theory.net
An online beginning music theory and ear training site. This site is for students to use at home to reinforce what they learn in class.
Other
The Basics of Reading Music
This site is an overview of how to read music. The basics of notation such as note and rest values, the names of lines and spaces of both treble and bass clefs, etc. are covered. Includes downloadable audio files.
Other
Basic Music Theory: Bar or Measure
This website is extremely valuable in that it describes topics in easy-to-understand language. Relatively easy to follow. Just use the hypertext links.