The Stained Glass Association of America (SGAA) is a trade organization for stained glass artists. It was originally founded in 1903 as The National Ornamental Glass Manufacturers Association of America.
With annual fees of $500 for fully accredited membership, most of the GlassFacts.Info readership probably won't rush to sign-up. That's okay -- the SGAA's focus seems to be on the tier of the stain glassed industry engaged in large-scale, architectural installations. No sun-catcher artists here :-)
Still, there's a lot of information on their website that any glass artist can put to use (or at least find interesting). Right now it may be a bit tough to find it all -- they are mid-redesign of the website and not all the links work. I've provided direct links below for some of the more interesting and useful content.