blarkman gave me the advice I needed to do mine. Only thing I can say is it is one of the best mods you can do. Pretty easy to do and makes a big difference. The only thing to be sure to do is get a quality padding not the cheap stuff from Lowes or HomeDepot. Go to a flooring store and get the quality stuff. Makes a big difference. As Bob says search under laminate and you will find a bunch of posts.
Good luck and let me know if you have any questions.