I get many of my silk scarves at Dharmatrading and some of my other silk supplies, such as dyes, gutta bottles, spray bottles and silk garments for painting. They produce a wonderful catalog full of information for the textile craft industry. Their website also has a lot of How To information.
Thai Silks (Retail) or Exotic Silks (Wholesale)
I get many of my silk scarves and most of my yardage from Exotic Silks in Mountainview CA. If you only need a little silk, use Thai Silk. If you buy in big quantities ($300 to start, $100 minimum after that) you can use Exotic Silks. They are two arms of the same company
Susan Louise Moyer
I get my brushes and frames from Susan and have taken a number of classes from her. Check her site for workshops. I think her book on Silk Painting is the best out there. Susan also sells a wonderful silk stretcher which she and her husband have developed over the years. She has a terrific resources links page at www.moyerdesign.com/links.htm
Silk Painters International
This website is used by a lot of well known silk artists to promote their work. You can see wonderful examples of silk paintings here. They also have a section called Silk Wiki which has a lot of How To information. You can become a member of Silk Painters International and get their SILKWORM publication.
Fashion in Harmony
This website has terrific information on making bias cut garments and their book, Bias Cut Blueprints is a must-have for any seamstress doing a lot of silk work. Fashion in Harmony also present workshops around the country.