AA and 12-Step Alternative Addiction Information - http://www.addictioninfo.org
Theories of addiction
http://www.addictioninfo.org/articles/1014/1/Theories-of-addiction/Page1.html
Addiction Alternatives
Addiction Alternatives is a service and related websites of Clinical Psychologist and addiction expert Marc F. Kern, PhD.

http://www.habitdoc.com 
By Addiction Alternatives
Published on 09/25/2006
 
This section of AddictionInfo presents a wide range of theories on the causes of addictive behavior.