Pipes in wall vibrate noisily when toilet is ...

I had to bring a guy in to take care of this. What he did was secure the pipes, and he said it had to be done because otherwise you increase chances of a break in one of the pipes, which could result in a leak in the walls.

I don't think there's an easy solution for this. 

jahan is rite, the reason is your pipes have come loose or were never held in place properly. the only solution to this is to secure the pipe, which for the most part means putting holes in your walls. you can do this yourself as all you need is metal strapping, some screws to hold the pipe and some drywall peices to repair the wall. this job would cost you about 25$ to do yourself or in the hundreds for a plumber to do it. just takes a little time

There's a much simpler and cheaper solution. Install a mini water hammer arrester on the toilet water supply line. Sioux Chief makes one just for toilets. http://www.siouxchief.com/B_Product_Detail.cfm?GroupID=350500

Here's the pdf file describing the problem and products available: http://www.siouxchief.com/PDF/MiniResterbrochure04.PDF

I had to put one on the cold and the hot water intake on my clothes washer and one of the toilets. They just screwed on. That was 12 years ago and still working. Great product.