Several different software companies have released their own firewalls and protection utilities. One of the oldest and most popular programs is called ZoneAlarm, by Zone Labs. ZoneAlarm comes in two different flavors: a pro version, which is a two-way firewall plus a boatload of other features, and a free version that is just the basic two-way firewall. ZoneAlarm is a differ ent type of firewall than the firewall that is included with Windows XP and Windows XP Service Pack 2. ZoneAlarm includes a special two-way firewall that not only blocks traffic that remote users are sending to your computer but also blocks traffic that your programs are trying to send out. Now, why would you want to block traffic that your computer is sending? Sometimes, people are concerned about their personal privacy and do not want their computer applications phon ing home to the developer's Web site sending usage data, checking for updates, or validating licenses. Additionally, it is nice to be abl...