Questions...they are never ending!!!

Okay, can someone give me an example of how I would allow all traffic from
my LAN side to go out, while limiting what can come into it?  Ie...I have 3
email servers on the LAN side which are 1:1 nat'd, I only want to allow
certain ports, say 143, 25, 10000 and 110.

TIA,

Scott
BTW-I LOVE m0n0!!!  It is super software!