Setting up a windows 2000 network

Your network can be either a domain or a workgroup. Without much instruction, you can manage to get a workgroup working, i think. however, imho, get the microsoft book for passing the exam on Windows 2000 Server. in it will be complete instructions for doing as you wish plus much valuable background information. Then you can take the certification test and you are off with a running start...
here is very brief overview of what you gotta have
more info on www.linksys.com and support.microsoft.com and many others about 'how to network'
switch or hub with enough ports for all devices (in your case probably 5 or 6)
ethernet patch cables for each device incl. broadband router if applic
link light both ends of patch cable when powered
tcpip protocol
microsoft client for windows networks
file and print sharing enabled (if applic)
workgroup name exactly the same on all
same subnet on all
same subnet mask on all
correctly configured gateway on all (easiest to get working fast: configure broadband router to be dhcp server, configure all pc's to be dhcp clients. later switch 'em to static ip addresses after you observer results of: ipconfig (winxp, 2k) winipcfg (win98)...
shared resource configured on at least one device
local accounts for all users on each computer

sgt_shultz is correct a book would be helpful. Reason being if you read the book and do their simulations you begin to get experience of what your are doing, why its being done, and what needs to be done to correct problems.

Computer wise:
As far as far as what type of equipment to get I would certainly get used computers for the workstations since they will be for training purposes. And one good pc for the server since it would be the most important one.

Networking Equipment:
Depending on how much you wanna learn I would suggest a used Cysco router\switch if you wanna get hard core(buy used\refurbished though) or a dlink\linsys router.

Although I haven't tried this, you could try "virtual PC". You can install several OSs on a computer and actually set them up simultaneously to create a network. Go to: http://www.microsoft.com/windowsxp/virtualpc/ and read up on it.
Now, if you already have your 4 computers and W2K server etc. you could try this: www.microsoft.com/windows2000/techinfo/planning/walkthroughs
take any spaces that appear in the address..out