There's been discussion on the "Interiors" board... go there and search for 'insulation'... here's one thread: http://www.stovebolt.com/bboard/cgi-bin//ultimatebb.cgi?ubb=get_topic;f=20;t=000274#000000 (sorry I forget how to shorten it up)
Basically Tom get the peel and stick as Ron suggests... it's a roofing patch product that comes in a roll. Lay that down all over your floor. I then got jute padding from a carpet place (forget the stuff the catalogs sell you).. use a 3M adhesive and put that over the sound deadener.
Third, cut strips of the deadener and attach it to the inner panels of your doors. You don't need to cover the whole door to make it effective.
