Ok, my computer isn't wanting to show me what to do since I don't have two network cards, so I can't guarantee this is right.
Go to control panel - network connections (I'm assuming you are running XP) then look at the Network Tasks bar on the left of the window. Click on Set up a home or small office network, and you should be able to do it from there.
Oh, and I would like to point out that you can get a 4 port hub for about $10 these days.