- A really cool web-app for your mobile device that can measure: acceleration, distances, frequency, etc.: http://www.phonelabs.net/
- The Spangler Effect : The Science of Sound. Part One & Part Two
- What is up w/ noises?
- Kahn Academy on Waves
Great physics resources (be sure to click around their resources too):
A great video resource (sometimes another point of view makes more sense): http://www.khanacademy.org/