I happened across this product a few days ago and have been evaluating it as a potential time-saver and also to streamline firewalls across multiple servers.
Firewall Builder is a front end for configuring several firewalls, including iptables, ipfilter, OpenBSD PF, and Cisco PIX.
It is critical that anyone moving to a GUI for firewall configuration first understand how to work with these firewalls from the command line and their native config files to insure proper configuration, however, that said, fwbuilder can save time and help you manage your firewall, as well as managing rules across different firewalls under your administration.
It does this by using a central database for your firewall rules, then enabling you to submit rules across differing firewall programs on differing platforms.
fwbuilder can be run on numerous platforms, including Linux, Unix, Solaris and Mac OS X (using Fink). There are rpms for Red Hat and SUSE and of course source installs across all supported platforms.
As a related side-note, Telconi Terminal offers graphical Cisco device configuration to Linux, Mac OS X, Unix and Windows systems. Telconi Terminal is currently a tech preview, so it is not necessarily going to be open source and very likely will come with a price tag.