Win2k and DNS single server set-up

I’m wanting to set up a small network with Win2k server and a few workstations. I’m wanting to use AD which requires DNS running internally but I also want to connect to my ISP and use my one IP address registration with them and internet connection sharing to serve my shoestring budget network. Can anyone point me at a resource to walk me through the set up of DNS since all the stuff I have found seems to assume multiple server setups with firewalls/proxy’s. I intend to use a software firewall on my one server. Is this possible and will it have any degree of security?
Thanks.