For a general overview about sustainable fabrics, you may want to read this article we wrote for the Spring 2009 issue of Living Crafts magazine
(downloads as a .pdf file).
To learn more about specific ecologically-friendly fabrics, sustainable choices, etc, visit the following sites (pages will open in a new window):
Resources for Sustainable Textile Businesses
Inspiration, Ideas, Projects, and More
Sustainable choices and Information
Green Business Resources