ZoneAlarm has been making security products for a number of years and they have a good reputation. I don’t have the resources to review or evaluate security products so I tend not to make specific recommendations (but I do recommend that you should invest in a good antivirus package).
For one day only ZoneAlarm has made their ForceField product free to use for one year. It blocks phishing sites (this is a good thing), blocks keyloggers, and has a host of other interesting security features.
If you don’t already have a security package that does everything (and why not?) then try this one out. As I said, ZoneAlarm has a good reputation for this kind of thing and “free” is a good price. Note that they ask for your name and email address.
Link: http://download.zonealarm.com/bin/free/sum/index.html – click on the red button.
More info about ForceField here.
Update: This offer has expired. Good computer security is very important (read some of the pages on this site to find out why) and it’s definitely worth paying for good software that keeps you safe. You should be using a package that constantly scans your PC for malware (viruses, trojans, etc), scans all web pages and updates itself daily. It’s a very good investment.