Linux as a wireless AP

[Paul Mooring]

  I've got a couple of old machines I use a routers around my house
(gentoo based iptables routers) that I'd like to use an old pci wireless
card to make my AP and get rid of my old WRT54G, does anyone know of a
way to do this? Hopefully with a decent howto or guide, or else know of
a reason why this is a bad idea/security problem. (btw I the wireless
card I have is a ralink, and I think I have an atheros around somewhere)