Here are a few interesting links that I've found useful. You'll have to use the BACK button to return to this page. 

Acoustics

• CCRMA, at Stanford University
• The Acoustical Society of America
• The WWW Virtual Library of Acoustics
• The Acoustics Page (lots of other sites link from here)
• McGill University.

Optics

• None available

Photonic Band Gap

• UCLA
• Iowa State University
• Redstone Arsenal