If you're looking for advice on configuring a firewall script, Oskar Andreasson's tutorial is excellent - go there first.
The rc.firewall.gateway.generic is a good starting point for a gateway/router box.
The rc.firewall.desktop.generic is a good starting point for a box directly connected to the internet.
The sshattacks file shows some example lines (and explanation) for using the recent match to help protect against the common brute force ssh attacks.
Name Last modified Size DescriptionApache/2.4.9 (Unix) Server at rlworkman.net Port 80
Parent Directory - rc.firewall.desktop.generic 12-Mar-2011 07:24 1.2K rc.firewall.gateway.generic 22-Jan-2011 17:06 5.5K sshattacks 31-Dec-2008 05:47 3.3K