Center for Internet Security http://www.cisecurity.org/

CERT (Carnegie Mellon) http://www.cert.org/

COAST (Computers, operation, audit, security and technology):  http://www.cerias.purdue.edu/coast/coast.html

Common Vulnerabilities and Exposures: http://cve.mitre.org/

Computer & Internet Security Resources by Virtual Librarian: http://www.virtuallibrarian.com/legal/ccsearch.html

Computers, Freedom & Privacy Conference http://www.cfp.org/

Encyclopedia of Computer Security http://www.itsecurity.com/defaultie5.htm

HoaxBusters: http://hoaxbusters.ciac.org/

Infosyssec http://www.infosyssec.org/infosyssec/index.html
The security portal for information security professionals

Infowar.com http://www.infowar.com/ 

KBeta Security Web http://www.kbeta.com/

McAffe Virus Information Library: http://vil.nai.com/vil/default.asp

Microsoft Hotfix and Security Bulletin Service: http://www.microsoft.com/technet/security/current.asp

Microsoft Security Page: http://www.microsoft.com/security/

NIST ICAT Vulnerability Database:  http://icat.nist.gov/icat.cfm

Northern Light Computer Viruses:  http://special.northernlight.com/compvirus/

NTBugTrac: http://www.ntbugtraq.com/

Open PGP Alliance:  http://www.openpgp.org/

SANS www.sans.org/tools.htm.  One of the premier web sites full of useful links and information. Provides links for many useful white papers from a variety of vendors.  

Sun Security Bulletins:  http://sunsolve.sun.com/pub-cgi/secBulletin.pl

TruSecure http://www.trusecure.com/  Security News

UC Davis Computer Security Lab:  http://seclab.cs.ucdavis.edu/

ZDNet Tech Update:  http://techupdate.zdnet.com/enterprise/security