djcbriggs - Forums, Newsgroups

Peer Project V1 and V2 - Foundational Exercises and Discussion (conceptart.org)

Very highly recommended! Put all your colour theory into practice and get friendly, well-informed feedback from other colour enthusiasts from around the world.
http://www.conceptart.org/forums/showthread.php?t=53517
http://www.conceptart.org/forums/showthread.php?t=76955

sci.engr.color: "The art, science, and industry of coloring".
http://groups.google.com/group/sci.engr.color/topics

Colourware: Education for the Colour Industry (includes forums for questions on many aspects of colour)
http://www.colourware.co.uk/

Ask a Color Scientist FAQ (Munsell Color Science Laboratory).
http://www.cis.rit.edu/mcsl/outreach/faq.php