How do I turn off Windows Firewall forever on a business network?

I have a network with a mixed bag of XP and W2000 Pro machines and the servers are also mixed- some W2000 and some W2003. Is there a group policy setting to disable all Windows Firewalls forever or a registry tweak to turn it off permanently? Its annoying to turn it off on a machine only for it to turn itself back on when a new user logs on that machine!
Thanks