As software firewalls I’ve used both ZoneAlarm and Sygate but recently I’d suggest the free Smoothwall http://www.smoothwall.org/ ideal if you have an old pc lying around you want to turn into a dedicated firewall, just install Smoothwall from CD without any in-depth Linux knowledge and you’re pretty well protected. Heres a good article/review on it. http://www.osnews.com/story.php?news_id=5897 It does require some networking knowledge but less knowledge than a full Linux install as it does all that work for you and is up and running very fast.