Also comodo personal firewall. It is an amazing firewall. It is almost the same thing as zonealarm pro but with a different interface and also free. The only thing you need to do is when you download the program from their site, you have to give them your email address like this they send you the lifetime serial # or else you will have the 30 day trial. Here is the link:
http://www.personalfirewall.comodo.com/