I have written an ipfwadm GUI configuration utility. It's GUI via Netscape... it creates a shell script to be used as a firewall based on the criteria you choose during the configuration. It can also install the firewall rules, uninstall them, check firewall status, and watch network traffic from the masqueraded connections. If anyone is interested in this, Check out:

http://www.ejj.net/~sonny/fwconfig/fwconfig.html

Sonny