I have an Ubuntu server (10.04) running nat and I understand how to forward ports using iptables which works fine and is only mildly painful. What is "the easy way" of doing this? Is there some nice wiz-bang-network-tool (like ufw) that makes simple port forwarding super simple.
There's plenty of web-based script generators that'll help you get your initial iptables rules setup for you; once you've created your base rules, it's trivial to edit and make changes afterwards. Once you get the hang of it, you won't need (and likely won't want) a GUI anymore:
http://easyfwgen.morizot.net/gen/index.php
http://www.mista.nu/iptables/
Firewall Builder 4.0 (open source, Windows/Linux/Mac OSX/BSD) looks interesting and could be useful for managing large deployments and/or complex rules: http://www.fwbuilder.org
Shorewall's been around for a while too and looks promising (haven't tried it either).
check out ipkungfoo.
http://freshmeat.net/projects/ipkungfu
or ..use shorewall but with the addition of webmin. webmins interface for shorewall is quite excellent.