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  Description
 Parent Directory                                 -   
 rc.firewall.desktop.generic 2011-03-12 07:24  1.2K  
 sshattacks                  2008-12-31 05:47  3.3K  
 rc.firewall.gateway.generic 2011-01-22 17:06  5.5K