Don Sanbrook at
Sound Deadener Showdown - Your Source for Sound Deadening Products and Information
His products are of very good quality and were the lowest price that I could find. In addition, his technical support was top notch. Even called him personally while performing the installation in my garage for his support/direction on my project. I can't say enough good things about my experience. Took something that I was dreading to do and made it enjoyable and a huge learning experience.
Take a look at a thread I made discussing my project:
Sound Deadening Installation - StarQuestClub.com