These are just a few resources that I find particularly valuable to photographers.
Summit Series of Workshops
Unparalleled Lighting, Adventure, Nature, and Sports Photography workshops.
Light: Science and Magic
The definitive technical book on understanding light.
Light Right
An understandable, clear, insightful book on photographic lighting.
Photo Attorney
Photography legal expert and attorney, Carolyn Wright.
Photoshelter
Absolutely the finest online archiving and distribution solution for images.
Strobist
A great resource for making the most of Speedlights.
The DAM Book
Digital asset management information for photographers.
The Photo Brigade
A remarkable website and podcast for photographers by photographers.