|MadSci Network: Physics|
Searching through the MSN archives, I have found that other people have already answered your question. This previous answer is exactly what you require; I would not have said anything different. This answer gives a lot of comments and links about mechanical and electromagnetic waves in general.
There is a wealth of information about all kinds of physics questions contained in the MSN archives -- just search and enjoy! :-)
Try the links in the MadSci Library for more information on Physics.