I recently came across an interactive guide that is featured on the BBC Parent's Music Room website. It's a web based interactive program that is designed to help you "understand key terms in music by bringing them to life with sounds and moving images." Below is a screenshot of the page, and here is the link, if you want to check it out for yourself:
http://www.bbc.co.uk/music/parents/activities/musicsense/index.shtml
