A sound wavelength calculator will give you the wavelength of any airborne acoustic frequency in inches, feet and meters.

Sinewaves can be combined to produce acoustic signals that mimic human speech. Here's a site that explains how this works. And here're sites that demonstrate sinewave speech: Site one and Site Two.

Information about cochlear implants (including audio demonstrations of the sound quality available with these prosthetic devices). Go here, here or here.

Animations that simulate the ear's key mechanical and neural events.

Bats emit "calls" some of which contain frequencies that exceed the upper limits of human hearing. Researchers can reformatted some bat sounds --shifting them down in frequency-- so that humans can hear them. Give a listen.

Turn your house into a musical instrument: a case study in environmental acoustics.

Here's a site from you which you can download a huge variety of different sounds (searchable using a search-engine interface).

The glass Armonica is a most unusual musical instrument. Here are examples of sounds produced by this instrument, and here's why it is no longer played.

A nice essay from the journal Physics Today on sound localization. This journal, by the way, is published by the American Institute of Physics.