ZoneAlarm by ZoneLabs

ZoneAlarm has a multitude of great features, a firewall, an application control, an Internet lock, and Zones.

The firewall controls the door to your computer and allows only traffic you understand and initiate. The application control allows you to decide which applications can and cannot use the Internet. The Internet lock blocks Internet traffic while your computer is unattended or while you're not using the Internet, and it can be activated automatically with your computer's screensaver or after a set period of inactivity; a great tool to use against attacks to your computer. Zones monitor all activity on your computer and alert you when a new application attempts to access the Internet; such as blocking spyware from sending information. Very easy to use and customizable to any PC. Recommended use with Windows XP.

Note: The Service Pack2 of Windows XP Windows Firewall can cause conflicts with ZoneAlarm, if you wish to use the program, disable the Windows Firewall in the services and start ZoneAlarm.

This review thanks to Jardin.