Definitions:
http://www.pale-reflections.com/ednos.asp?page=orthorexia
http://www.wordspy.com/words/orthorexia.asp
http://www.worldwidewords.org/turnsofphrase/tp-ort1.htm
http://www.medterms.com/script/main/art.asp?articlekey=19891
Articles:
WebMD -- Orthorexia: Good Diets Gone Bad
BeyondVeg -- Clarifying Orthorexia
BeyondVeg -- Eating Our Way to God: A Poem
BeyondVeg -- The Psychology of "Perfect" or Extreme Diets
Medical News Today -- Obsessed With Eating to Improve Your Health
Psychology Today -- Orthorexia: Too Healthy?
XtraMSN -- Orthorexia: Hollywood's New Eating Disorder
Personal Accounts:
BeyondVeg -- Kate Finn
BeyondVeg -- Roy Holman
BeyondVeg -- Tom Billings
Orthorexia.com -- Steven Bratman
Books:
Health Food Junkies : Orthorexia Nervosa: Overcoming the Obsession with Healthful Eating