Birds in the Band - an interactive animated story about a group of birds who tire of singing alone and start a band; features several instruments
NEA: Jazz in the Schools - explores jazz music as an original American art form and as a way to understand American history: text articles, timelines, music clips, and biographies of major artists
New York Philharmonic Kidzone - loads of fun stuff and information: games, instruments, make your own instruments, compose your own songs, learn about current and past performers, conductors, and composers, news headlines from musical time periods, and more! Need a high-speed Internet connection and Adobe Shockwave for most of the activities
SFS Kids - learn all about music basics (staff, notes, tempo, rhythm, pitch, harmony, symbols, etc), orchestra instruments, and listen to famous orchestra pieces, compose, or play your own music; from the San Francisco Symphony. The color-coded piano that you can play online is especially fun!