setting up nat

[Antoine]

Hi,
I am relatively new to fedora (just done two years of gentoo), and
quite a bit of googling didn't turn up any easy way to activate nat. I
have a few machines that I want to be nat'ed through a fc5 box
connecting via pppoe. I installed firestarter but it won't activate
nat until I restart my adsl connection (which means sshing into my
router box and restarting... ok for me but not for the missus!). I
can't believe there is no standard way to set up nat, so if anyone has
any pointers I am all ears.
Cheers
Antoine

-- 
This is where I should put some witty comment.