eSecurity Planet 
A resource for daily information on e-security targeted to IT managers. The site provides users with information from a variety of sources, including experts at security product and services firms, and the consultants who follow the security industry.
Know Your Enemy
The Tools and Methodologies of the Script Kiddie
Know Your Enemy: II
How to track the movements of a Script Kiddie on your system.
Know Your Enemy: III
What happens once a Script Kiddie gains root. Specifically, how they cover their tracks and what they do next.
Playing With Fire: No Sweet Honeypots
One layer of defense in depth can be achieved through the uses of Honeypots to gain direct, observable knowledge of how Black Hat hackers operate.
The Honeynet Project
The Honeynet Project is a group of 30 security professionals dedicated to learning the tools, tactics, and motives of the blackhat community and sharing those lessons learned.
SecurityTracker.com
Information on the latest security vulnerabilities, free SecurityTracker Alerts, and customized vulnerability notification services.
IE 7
Firefox 2.0
