General Music Sites
Carnegie Hall Online Resource Center: For K-12 Educators, Games & Listening Guides, Master Classes, For Teaching Artists, Performances, and Artist Interviews
Learn Listening Online: Scottish government project but very useful for all music teaching
ArtsAlive.ca - Music: Orchestra resources
Musical Instruments at the Library of Congress
Classical Music Quizzes and Classical Music Trivia -- Fun Trivia
MusicTech.net (a comprehensive website in support of music education and technology maintained by Joe Pisano)
Elementary & Middle School Sites
America's Story from the Library of Congress (music materials throughout the stories)
Jr. High & High School Resources
Smithsonian Folkways music site
Ricci Adams' Music theory.net: one of the most comprehensive set of theory training online materials
Teoria: Music Theory Web: another long-standing, comprehensive set of online theory training materials
Sojurn: The Canons and Fugues of J.S. Bach: advanced but most comprehensive Bach interactive study materials online