I saw a Wired blog post recently that explains how you can opt out from receiving the yellow pages. (Be warned that the author really doesn't like getting that brick of bound pages on his door step.) If you too would like to discontinue delivery, simply go to the Yellow Pages Opt Out website and put in your ZIP code. You do have to register, but it's free and then you can select which products you want or don't want to receive anymore.
Also on the site you can find out how to recycle your yellow pages and learn about how the book gets made. (For anyone who is curious, Yellow Pages does its best to be environmentally friendly before and after printing the books.)