HackerThreads.org - Security Forum:Discussion forums with tutorials, Hacking programs and miscellanious threads.
HFX International Forum: Discussion forum for topics surrounding the underground, technology and the like.
SecureRoot: One of the worlds longest established hacking forums, offering resources covering everything from cracking to phreaking.
SecurityRisk.Org: Many topics and threads about Vulnerabilities, Hacking, Phreaking, and programming. Informative and active.
Social Engineering: Discussion forum about the insecurity of humans known as social engineering.
Spywire Forums: Forum dedicated to bringing knowledge to people starting out in hacking.
The Forbidden Web Archive: Security and Development Forum with a Security Basics Forum and Vuln-Dev.
