I've been doing some reading and there has been a bit of discussion about this on the thread below
http://www.camaro5.com/forums/showth...t=51910&page=5
Read down the whole page. Seems it could be debris in the sway links or they are getting worn or possibly strut mount clogged with debris and binding. But it seems like the noise is coming from the front end suspension vibrating, unless the noise is coming from the rear.
Just trying to be sure it isn't something more serious like my trans or rear diff. Let me know what you guys think.