Try googling "dp9 site: www.quiltingboard.com" I came up with many links to the QB and disappearing 9 patch.
Moda Bake shop and Missouri Star Quilt both have instructions on how to make a DP9. There are other places with instructions, too. Here's a link to another tute:
http://www.psiquilt.com/2009/03/disa...ial-super.html