IB Music is organized into two major volumes: Music History and Music Theory. Preceding both is a short introduction to the study of music. You will need to be familiar with all of these sections to analyze a piece of music well.
http://keepingscore.org/ for looking at scores, music history..
music history & different forms http://www.patriciagray.net/Musichtmls/Flash/flash.html
http://musicatschool.wordpress.com/ charts of techniques used in different types of music
http://rpfuller.com/gcse/music/ GCSE music history notes
http://www.bbc.co.uk/schools/gcsebitesize/music/ GCSE bitesize,great site for basic theory & listening
http://www.uwosh.edu/faculty_staff/liske/musicalelements/index.html Examples of the different types of textures
Brilliant site http://www.musiclisteningrevision.co.uk/higher/learnconcepts.htm it also has a brilliant listening glossary:http://www.ltscotland.org.uk/nq/resources/learnlisteningonline/atozdictionary/index.asp other listening glossary from free online book http://www.wwnorton.com/college/music/enj9/chronological/index.htm
voices in opera http://arts.endow.gov/national/GAV/voicetypes.html