There is really nothing to it, XP has file and printer sharing by default, you might have to enable NETbios over TCP/IP in the network properties, but that is about it. The networking wizard screws up more networks than it configures. If you have a router and use DHCP, you basically plug the computers in and it works.
If you are using XP Pro, disable simple file sharing then use user accounts with passwords. Then you can use NTFS security permissions to manage your shares. It is very simple, most of the time people over complicate it.