Well you have a few options:
1) you can go the wireless route getting two wireless cards for the systems available at any computer retail store. (If these are both desktops get the desktop PCI wireless cards)
2) you can run Cat 5 all over your house and link them that way. Its actually really easy and if you do it right will be the better setup for speed in the future of High Speed internet esp. with the coming advancements. However this requires you to buy cat 5 cabling and also to decided where you want the router/hub setup to be. You can do a setup away from both computers (say in a closet thats inbetween both and out of sight). Or you can put it next to one of the computers.
Ok with the #2 setup you will be faster than going the wireless 802.11b route but if you upgrade to 802.11g you would have a good wireless system. I personally use wireless because I have laptops. If you have desktops it is your choice but if you ever plan on adding a laptop, you can get a router that adds in wireless as well. These are the things you will need for your setup either way:
1)Router (Linksys Wireless 802.11g is like 70)
2)PCI Wireless cards (Only if you want the desktops wireless)
3)Cat 5 cable (Only if your doing the Wired route)
4)PCMICA Wireless Cards (To match the router for laptops)
5)USB Wireless points (Work for desktops as well but slower, also works for the XBOX I believe not sure there)
6)Hub (Only for the wired route, its just good to have for future computers and makes things easier)
7)Network (Cat 5) cards if your systems do not have them (Wired setup only)
Thats the basics to get started. As you can see I like LinkSys. Thats what we used in the military when I was enlisted. I use an airport base station at home but thats only because I had one and wasn't using it so I decided to save the money, works fine. But if your a PC user just stick with something you can work with via the PC. Now you also might want to watch all the programs these wireless cards and Routers use. Ignore any wireless programs just use the disk they send for drivers. Install the Router programs so you can setup personal settings on them. That should get you going easily. (Esp if you buy different brands and mix them) Also I would recommend only installing the wireless router setup on one system, this way only one system has access to it and you can limit that access to making changes that could lead to problems if you didn't.
