Make sure you have Windows 98 Second Edition. There are so many different ways to do this you should pick one that suits your business needs and desires
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cheapest way: You can run a single network cord between the 2 machines for now, but I'd buy a little hub/switch which will allow for easy expanding.
Here's an 8-port switch for $20 after shipping!
and if you dont have network cards in your machine: $7 each after shipping!
Set up a windows network with file and printer sharing, and if youre going to use the internet, 1 connection to 1 computer (whether dial-up, DSL, cable, whatever) can be shared from the connected computer to all the others with the built in Windows Internet Connection Sharing (ICS). Walk-throughs on how to do this (setting up IP addresses, workgroups, protocols, file sharing, ICS, etc.) are all over the internet.
downfalls: the main computer that connects to the internet must be turned on in order for the others to be online. And if you eventually get alot of users online, the internet may bog down a bit being fed through 1 machine.
total cost for 2 machines if you need cards and get a switch, about $50 (cant forget the CAT5 Network cable).
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If you have a broadband connecion, you could spend a few more bucks and use a router for a more efficient way of distributing your internet connection. and you dont have to have one main computer turned on in order for the others to have internet access. the internet feeds into the router, then goes out to each machine.
8 port router after shipping: $55.50
total cost for your setup would end up being about $90
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Or you could make your network completely wireless (most expensive, but you dont have to run wires everywhere)! or you could have some wireless and some wired with the same router below( my recommendation)...
Wireless adapters: $43 each after shipping
4-port switch/Wireless router: $59 after shipping
total cost for completely wireless with 2 machines: $145
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this is the hardware part. explaining how to set it up would take up too much space (as if this didnt). Do a little google search and surly you can find a site that tells how to set up windows for networking, or maybe someone here can recommend one. i'm too tired to look now...hardware is the first step though! each of these setups can share printers, files, and internet connection. And I made sure to find name brand hardware cause it does make a difference when it comes to networking (like dlink and netgear). good luck
I suppose I should direct my response to a specific individual instead of mulling over all posts in the thread in a single response. 
