A peer2peer is the simplest network you can make, the least you need is 2 computers and a way to network them together. Most networks operate in a star form,

and as so most network kits you can buy have a hub, network cable and 2 network cards. but if you run an old network it might be a bus,

Just for the record a bus is 1 long segment of network cable that all the computers link off, it is a bit like the electric ring in a house and every socket is where a computer would plug in. In a peer2peer network with Windows 2000 you must make sure that all the computers are set-up the same, so if you have the user bob on computer A then you must have the user bob on any other computer so that bob can use all the shares on computer A over the network. That is not the same for a windows 9X only networks, but if you have windows 2000 and windows 9X you must have exactly the same password and user name, or windows 2000 will tell you that you do not have permission.