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.

Microsoft Tech Net: Threats and Countermeasures
The Threats and Countermeasures guide provides you with a reference to all security settings that provide countermeasures for specific threats against current versions of the Microsoft Windows operating systems.

Sana Security
Providers of real-time security prevention solutions.