The first component you will need is a Network Card,
which is your "transmitter" sending signals to the hub and other
computers. These come in a variety of forms:
Though a basic 10 MB PCI card is more then enough for gaming,
you should really look into 10/100 MB PCI card, especially if
you're going to transmit large files from one computer to another.
Usually the prices differ only slightly, depending on manufacture,
shop online to get the best deals, personally I'd go for 3Com
network cards since they are regarded as the industry standard,
but don't take my word on it! As I personally have a cheapo
card installed so it really depends on the amount of money you
are willing to spend.
you purchase remember to check if you have free PCI ports, these
are white slots on the motherboard, and avoid buying ISA cards,
just take our word for it, don't even if that's the only card
you can purchase.
Now there are Combo packs that actually contain the full setup
of network cards, hubs and cables that you'd require, these
save a lot of money buying all the network cards, cables, hub
individually, so don't be frightened to purchase one to save
up on some serious cash, for example The Kingston
SOHO (small office, home office) networking bundles/kits that
even have dead easy instructions how to set up your own network
in a snap.