(212) 613-8020 (phone)
(212) 613-8021 (fax)
http://www.drugpolicy.org/about/
Supported by the Lindesmith Center, one of philanthropist George Soros' policy reform organizations, the Drug Policy Alliance Network is one of the nation's largest organizations working to change the existing drug laws. Starting in 1996 with the California Medical Marijuana initiative, Prop. 215, DPAN has led political campaigns all over the country to decriminalize drug use and divert minor drug offenders out of the criminal justice system.
The organization has a node on its website that contains links to drug policy reform organizations all over the U.S.: http://www.csdp.org/links.htm.