I used to have an iMac and an iBook and we used an ethernet hub to do internet sharing, where the iMac was the server. This worked okay but it's not the fastest option. A hub transmits information to ALL computers that are connected to it, regardless of whether it's meant to go to them or not, and splits the available bandwidth between the 4. Obviously this is inefficent and cripples the speed. It did work okay for filesharing and sharing interent but could've been faster. A `switch` is more suitable than a hub since it makes full-speed specific connections to each computer, to send them only the data that applies to them, which saves a lot of bandwidth and makes the whole thing faster. Then from there you can move up to a router with a built in switch, since a router will offer you lots of other features like firewalls, wireless connections, security features, etc.
I just moved to a TrendNet TEW-452BRP Wireless router. It was $49.99 from CompUSA. It was a bit tricky to get it set up on a Mac and we had to call customer service, but eventually it worked fine. We have one computer connected to one of its 4 10/100 ports, by wire, and then will have another computer connect via wireless. It has a built in switch and can do filesharing and all that. If you only have four computers this router would probably be good enough, and if you make all your systems wireless you should have no problem. Only thing to bear in mind is you probably need at least one wire, temporarily, to do admin/config changes to the router.
I just moved to a TrendNet TEW-452BRP Wireless router. It was $49.99 from CompUSA. It was a bit tricky to get it set up on a Mac and we had to call customer service, but eventually it worked fine. We have one computer connected to one of its 4 10/100 ports, by wire, and then will have another computer connect via wireless. It has a built in switch and can do filesharing and all that. If you only have four computers this router would probably be good enough, and if you make all your systems wireless you should have no problem. Only thing to bear in mind is you probably need at least one wire, temporarily, to do admin/config changes to the router.