University level tutorials on mainly shock and vibration in Acrobat PDF format are found at Vibrationdata.com. Also some freeware is found here.
Basic tutorial on sound Campanella Acoustics
Noisenet, not only a directory of all British companies, but listed on the environmental page are the
On active noise control you'll find answers to your questions at Chris Ruckman
Acoustic properties of solids, gases, liquids ultrasonic
Underwater acoustics at the whale acoustics project
Very nice journey trough the ear (TIP!!)
"Good neighbors keep their noise to themselves." is the slogan of Noise Pollution Clearinghouse. You'll found lots of information on environmental and occupational noise.
Another on environmental noise is NoiseWatch Online
Search a company on acoustics at Ecgcorp
Vibration absorbing material with nomogram has Heathcote
Interesting technology to send acoustic signals through automotive structure is found at Maycom
More links on noise and vibration
Audio dictionary Hundreds of audio terms.
Roberts "hifi on www" seems complete on hifi, including an extensive faq page.