Chats and Forums

The Forbidden Web Archive - Security and Development Forum with a Security Basics Forum and Vuln-Dev.
www.forbiddenweb.org/

HFX International Forum - Discussion forum for topics surrounding the underground, technology and the like.
forum.hfactorx.org/

SecureRoot - One of the worlds longest established hacking forums, offering resources covering everything from cracking to phreaking.
www.secureroot.com

Social Engineering - Discussion forum about the insecurity of humans known as social engineering.
www.socialengineering101.com

Irvine Underground Forums - Discussion forum for Southern California security experts and hackers. [RSS]
ivu.irvineunderground.org/