CyberCop ASaP Zombie Scan - free scanning service to ensure that systems are not running the Zombie agents, and are not vulnerable to having these agents deployed on them.
Security Focus - computer security information clearinghouse. Includes a calendar, free tools, forums, industry news, and a library.
AntiOnline - discussion forums, security downloads, event listings, an explanation of hacker jargon, and more.
Insecure.org - miscellaneous technical security information and tools.
The Ultimate DeCSS Resource Site - resources and information on DeCSS, a utility that decrypts CSS, a form of data encryption used to discourage reading media files.