I've been using ZoneAlarm for nearly a year now. I've found it easy to install and easy to live with. And it has saved my read end on more than a few occasions.

I discovered a Matrix infection when ZoneAlarm alerted me to the fact that a new program was trying to access the internet. I checked it out and found my Virus detection database was out-dated and I'd let in a virus. A virus that was trying to talk to his friends and cause more damage. ZoneAlarm stopped the virus and as a result alerted me to the exist of the virus.

I've also detected a couple of programs with embedded Spyware. After installing the programs they tried to phone home with information about my computer. ZoneAlarm alerted me to this and I was able to eliminate the Spyware using the OptOut Utility from Gibson Research Corporation. That was fun.

I've also had the pleasure of watching ZoneAlarm stop portscanning hackers from accessing my computer effective making my computer invisible to the internet. Another good thing.

Normally I wouldn't encourage newbies to get involved in firewalls and the like -- too complicated with uncertain results. However, with ZoneAlarm I'd say go ahead give it a go. The download is free for personal or non-profit use. And with the new tests ZoneAlarm has been shown to be king of the mountain when it comes to keeping track of who and what your computer talks to.

When an application on your computer tries to access the Internet, ZoneAlarm makes sure it has your permission first. This ensures that a rogue program will not sneak your important data out onto the Internet. Here you can see a sample window. ZoneAlarm is asking permission for this program to access the internet. You'll notice you can give permission on a one time only basis or on a permanent basis.
 
ZoneAlarm has the wonderful capacity of not only blocking outside traffic, it can make your computer invisible. This "Stealth" mode makes your computer look like it's not even logged on. When the firewall blocks Internet communications it will issue an Alert in order for you to be aware of the blocked activity.
 
As mentioned earlier. ZoneAlarm is free for personal use. And for business use the registration fee if very reasonable. Just stopping one hacker attack or spyware miscreant is worth it.