A fellow named Danny Kay tried to post this to the old forum. It is a good set of links.
PWF stands for Permanent Wood Foundation and it is also called a PT wood foundation.
The Permanent Wood Foundation is a very viable foundation for areas where concrete is difficult to deliver or for owner-builders who want to use standard framing techniques with only a few new details to learn. Such foundations are particularity good for a basement that will be finished out. The finished space is larger, and more comfortable than would be the case in a concrete basement. Such a framing system is also good for earth sheltered designs.
Kay suggests having a third party inspection. He found information and links to inspectors at these web sites. http://www.southernpine.com and http://www.cwc.ca.
The Southern Pine Council (http://www.southernpine.com/library-pwf.htm) has free and low cost publications on PWF. This is some of the best information available and anyone planning to build using this system should get a copy of the free "Design and Construction Guide (http://newstore.southernpine.com/cgi-bin/newsopine/product?;32;)".
http://www.pwfs.com/index123456789.html - has slide shows of PWF installations and more information.
Note: in some areas of the country foundation grade wood is made from wood species other than southern pine. The construction details are the same, however.
The links for this are out of date. Here are some new links.
http://www.southernpine.com/applications/permanent-wood-foundations/
http://www.jlconline.com/basement/permanent-wood-foundations.aspx
Thanks for updating that. :D It is still an option to consider for some projects.