Chess in the Air - deep and thoughtful source of information on soaring theory and practice
Bruno's YouTube Channel - Soaring pilot Bruno Vassel's amazing collection of HD soaring videos
The Secret Life of a Glider Pilot - Kelly Teagle's blog, who flies with the Yorkshire Gliding Club in Thirsk, UK
Williams Soaring Center - Located just north of Sacramento, CA. Williams is a great soaring site and has excellent modern equipment.
Arizona Soaring - Located at the foot of Estrella mountains south of Phoenix. Estrella is the largest teaching center in the US. In addition to their very active primary program, they also have a well known aerobatic program taught in Grob 103's. Estrella Sailport is a great place to get an early jump on the soaring season.
BigSky Soaring - A soaring gem just north of Yellowstone NP. Thermals to 18k+, fantastic views, private airport, great hosts - Greg provides instruction/DPE, Ursula is a very experienced tow pilot
Evergreen Soaring - Operating from Arlington, WA
Puget Sound Soaring Association - Operating from Enumclaw, WA
Seattle Glider Council - Operating from Ephrata, WA
Spokane Soaring Society - Operating from Deer Park Airport
Hood River Soaring - Operating from Hood River, OR
Sailplane dealers and merchandisers
Blanik America - Importer of Sportine Aviacija's line of high performance sailplanes. Operated by club member Vitek Siroky.
Cumulus Soaring - Operated by Paul Remede, Cumulus Soaring has a wide selection of soaring supplies and equipment. Paul has some very helpful product comparisons and selection guides on his site.
Wings and Wheels - Has an extensive selection of soaring equipment and supplies.
Wings and Wheels (classified) - great place to check out used gliders!
Glider Books - Russel Holtz's glider training materials. His Glider Pilot's Handbook of Aeronautical Knowledge and Flight Training Manual for Gliders are excellent.