There is a fair amount of networking information on the Linksys website click here if you want to use a cheap wired router/switch then the Linksys 4 port BEFSR41 will accept connection from four PC's. Checkout the wizard to see how it is all set up from this link click here
and a wireless network card in each machine - that's all.
If you don't want to go the wireless route you can connect a broadband router to each machine via standard Cat5 networking cable, but then you've got to run the cable from room to room. You may not be in the same house next year,and if you do move you'll have to go through the same procedure all over again.
My advice is to go with wireless networking - a good router (from Netgear or Linksys) will cover the whole house and take an hour to set up.
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