Art Glass World
Contains listings of associations, clubs, retail outlets and glass studios across the US, plus some free patterns and photo gallery.
http://www.artglassworld.com/
Silicon Folly
Stone and glass work, including instruction manuals for stepping stones, stained glass and hot glass, and forums.
http://www.siliconfolly.com/
Wardell Publications
Publisher of design, instructional, and pattern books.
http://www.wardellpublications.com/
Warm Glass
Features an online tutorial forum and information on equipment, processes and techniques. Offers a technical book on warm glass.
http://www.warmglass.com/