A firewall is a hardware or software system designed to prevent unauthorized access to or from a private network (i.e. your computer at home or work). There are many firewalls available for use, some are on subscription basis others are free. Below are links to some firewall options. The key to sucessfully implementing a firewall is reading the user's manual, whether it be online, or within the firewall program itself.
Widely considered one of the best anti-virus program developers, Symantec includes a firewall with their Systemworks package. Symantec products tend to be somewhat expensive though.
McAffee is another widely known name, however I have found it to be unreliable. Costs money to use after a trial period.
Kerio. Ahhhhhh pure firewall goodness. I use this one, it was bundled with a magazine I bought. Excellent program, however it requires a little bit of learning to use. You can use this one for free.
In my opinion, nearly worthless. As far as user friendliness goes it's #1.....sometimes.
