Sounds like you have loose pipes. I had a similar problem. Go to a harware store and get the correct clamps for your type of pipe. Copper clamps for copper pipe for example to prohibit corroding. And make sure you get the pipe tight to the walls and or ceilings. That should do it. It is caused by pressure changes, that is why pipes are clamped done.
Originally posted by steph: whenever i turn on hot or cold water anywhere in the house (20 years old), the main water supply pipe to the house starts shaking. This is a new isolated occurance. What is the problem?