Radiant Imaging
CCD light measurement systems, light source characterization files, optical and illumination design software, and optical and illumination engineering services.
http://www.radimg.com/

Volpi Manufacturing USA
An online store for fiber optic, cold light sources for microscopy and other heat-sensitive illumination applications.
http://www.volpiusa.com

Fiberoptics Technology Inc.
Manufacturing standard and custom fiber optic cables, fiber optic lighting, and fiber optic illumination products for industrial, medical, and commercial industries since 1977
http://www.fiberoptix.com/

Lumitek International
Supply electroluminescent (EL) lamps which are flexible, flat, thin, cold illumination sources and can be cut into complex shapes.
http://www.lumitek.com/Perma2.html

Aristo Grid Lamp Products, Inc.
Designer and manufacturer of light sources, including cold light enlarger heads.
http://www.aristogrid.com/

Charleston Gas Light
Handcrafted Copper Lanterns made in Charleston, SC (in gas or electric) using
http://www.charlestongaslight.com

Philip Dutré's Publications
Mostly relating to global illumination algorithms and monte carlo light tracing.
http://www.graphics.cornell.edu/~phil/PUBLICATIONS/publications.html

Light Tec
Welcome at Light Tec, European Distributor of Optical Design Software and Measurements System : telecommunication design, optical system design, video photometer, color measurements...
http://www.lighttec.fr/

finalRender
Featuring full global illumination, advanced raytracing and subsurface light scattering support, created by cebas.
http://www.finalrender.com/

3D Scene
Illustrates most of the modeling, illumination, and rendering 3D objects. Covers Z-buffer, Shading, Phong illumination, and Ray Tracing.
http://www3.telus.net/Voiculescu/scene_3d/index.html