Astalavista Group: Don't let hackers, crackers, phone phreaks, or script kiddies catch you off guard. Find the latest news from the IT underground on this site.

CERT Coordination Center: This is Carnegie Mellon Software Engineering Institute’s center for Internet security expertise.

Drizzle.com: This is the unofficial guide to wireless security issues—a fascinating page and a great starting point for exploring this topic.

Spam Abuse: This site has been helping the public fight spam since 1996. A good place to go to learn how to most effectively protect your organization from this menace.

Spywareinfo.com: Learn how to protect your users from the growing threat of spyware and stay informed about the latest threats and techniques for averting them.

Symantec Antivirus Research Center: This site is essential for users of Norton Antivirus software. In fact, even if you don't use Norton Antivirus, it's one of best sources of virus information on the Web.

Vmyths.com: Want to know if the latest virus scare is real? Vmyths.com offers straightforward info about computer virus myths, hoaxes, and urban legends.