There are hundreds of resources out there on the internet for the stained glass artist/hobbyist/appreciator. These are a few of the ones that I consider useful.
An art glass studio in Dallas, TX. The front half of their store is an art glass gallery. In the back is the studio, where they sell fused and stained glass supplies. They also offer classes.
An art glass supplier in Lewisville, TX. They have an online store and offer fusing and stained glass classes.
Offers the Glass Eye 2000 stained glass pattern design software. Free 30 day trial download.
Patterns
Sister sites providing lots of free patterns. Includes Chinease characters, celtic knots, flowers, birds, panels, lamps, boxes, and more!
Supplies
Several sites for purchasing glass nuggets and other glass supplies.
They carry beads, cabochons, chain, findings, and filigrees. Great for adding a unique look to your glass project.
Tutorials
Instructions for constructing copper foil and lead came stained glass projects. Good step-by-step tutorials with pictures.