What is Music Theory? Posters like this for intervals, scales, circle of fifths, etc.
FREE Printable: Music Math Cards - O For Tuna! Elementary Orff Schulwerk
Kids can learn music theory, piano, guitar, and more with these FREE online music resources!
Music Theory Review (Music Bingo) - site has MANY more music games/flashcards. http://www.susanparadis.com
A fun way to help kid learn the notes of the music stave that really works!
Worksheets - Vivo Harmonics Music
This is pretty much what I'm doing in my music theory class right now...
Khan Academy for music! Tons of video lessons to show in class or provide as a resource for students to study tricky concepts/ideas.
The pic featured is a great illustration of the connection between the piano keyboard, the staff and it's similarity to walking up the proverbial alphabetical staircase.
The week's blog demystifies key signatures. Complete with the Circle of Fifths!