Working with IPTables

[Christian]

Hi all,
I have been trying out a graphical user interface for IPTables called Firestarter. But it doesn't work that good with Orca, or at least adding a rule from the policy tab doesn't work that good. So, how do I add a rule manually?
I have also been looking at a very simple command line based interface wich I think interacts with IPTalbe in Ubuntu Hardy called ufw. You just specify the service you want or port you want to open and it's very easy.
But, if I want to play around with IPTables directly, any tips?
Many thanks,
Christian