The World Health Organization provides useful information about substance abuse, including alcohol, here: http://www.who.int/substance_abuse/en/

The National Institute for Alcohol Abuse and Alcoholism: http://www.niaaa.nih.gov/

Information page on naltrexone for treating alcohol abuse, from the US Department of Health and Human Services: http://ncadi.samhsa.gov/govpubs/BKD268/28c.aspx