This is not a comprehensive list of all the links that we sprinkle through the chapter pages listed at the left, but rather a select list of "universal" links, comprehensive and authoritative sources that readers of Why You Hear What You Hear will want to access.
1) The University of New South Wales is a world leader in acoustics and especially musical acoustics. Their web resources are excellent: http://www.phys.unsw.edu.au/music/
2) Prof. Joe Wolfe of the University of New South Wales has an extensive collection of sound (and other physics topics) animations and instructional videos; see http://www.animations.physics.unsw.edu.au.
3) The Hyperphysics web site covers much of physics; it has a sub-section on Sound and Hearing, http://hyperphysics.phy-astr.gsu.edu/hbase/hframe.html
4) Stanford University Center for Computer Research in Music and Acoustics (CCRMA) serves the Center's immediate community but also has many interesting facets, such as the Chavín de Huántar Archaeological Acoustics Project.
5) Dan Russell's acoustics website, with many clever animatied gifs and insights about vibrational modes of objects like baseball bats and beer bottles, acoustics of guitars, and more, http://www.acs.psu.edu/drussell/