Toxyn Technologies, Inc.  
   Hacking related group.
   http://www.toxyn.org/

Pulhas WebSite  
   A collection of current hacker news articles.
   http://p.ulh.as/

Eleventh Alliance  
   Offers details regarding select viruses, overflow and security exploits, bios tools, and crytography. Also features book reviews on assembly programming and computer security.
   http://www.11a.nu/

Cult of the Dead Cow  
   Offers team background, tools and BackOrifice downloads, and news archive.
   http://www.cultdeadcow.com/

Twentythreedotorg  
   SoCal's hacking group. Canadian free since 1999.
   http://www.23.org/

Progenic Security  
   Security advice and exploits.
   http://www.progenic.com/

HackHull  
   Group of hackers in the United Kingdom. Information about meetings, projects, and links to personal pages.
   http://www.hackhull.com/

Moloch Industries  
   A New York hacker group.
   http://www.moloch.org/

The Dark Side  
   Offers tutorials and articles on security related content, hacking, cracking, and network exploits.
   http://www.darknet.org.uk/

Digital Information Society  
   Exploit archive, phreaking information, and group member pages.
   http://www.phreak.org/

Attrition.org  
   Attrition is an eclectic collection of internet and computer security resources.
   http://www.attrition.org/

Synnergy Networks  
   Security research site with quality papers and exploits
   http://www.synnergy.net/

CyberWarrior Main Base  
   CyberWarrior specializes in tutorials, downloads ,and other information.
   http://cyberwarrior.gq.nu/

Crewl Underground Madness  
   Belgian group specialized in computer and network (in)security, hacking, coding and phreaking.
   http://www.blackhat.be/

CyberArmy  
   Internet security group focusing on internet deregulation. Also provides tools for anonymity, password cracking, port scanning, remote administration and firewalls.
   http://www.cyberarmy.com/

Razor  
   Team of security researchers. Features news, original papers and advisories, presentations they have given, and tools they have written.
   http://razor.bindview.com/

TwistedinterneT ServiceS International Inc.  
   Underground Hacker site with an extensive archive and library.
   http://www.twistedinternet.com/

HATE (Hackers Against Tyranny Everywhere)  
   Anarchy, HAcking, Phreaking files for newbies.
   http://hnsg.net/

enZo  
   Coding group. Offer hacking tools and vulnerability exploits.
   http://www.enZotech.net/

Netric Security Team  
   Research site containing papers, tools, shellcode, exploit code, advisories and team projects. Portions are in Dutch, however the majority is in English. Majority of code available is written in C or asm.
   http://www.netric.org/

Nomad Mobile Research Centre  
   Hacker lab engaged in vulnerabilities research. Security papers, full disclosure advisories and current projects. Also features a FAQ on hacking techniques.
   http://www.nmrc.org/

Xfocus  
   Organization dedicated to the research and demonstration of vulnerabilities in network services and communication security. Offers papers, security tools, exploit code, advisories and a discussion forum.
   http://www.xfocus.org/