I would go the router/hub route if you can - it's a lot nicer than internet connection sharing, as you'll always need to PC connected to the internet switched on.
We're only on ISDN here (too far from the exchange for ADSL), and I use an ISDN router which has a 4 port hub included. Cabled up the house in various places, and it works beautifully. Switxh any PC on, and instant internet access.
For broadband, it will be a similar setup, except you'll need a cable router as mentioned above. The router will have a web like interface to it, accessed through an internal IP address. Here you can enter the connection details such as usernames, passwords etc. Then set your PCs to connect to the internet via LAN, and set the gateway as the router's IP address. Whenever a PC tried to get internet, it will hit the router, which will then pass on the request to the cable modem, and off you go.
A little more expensive, perhaps (cost of router), but well worth it. Good website for more info is
this one - lots of info as well as stuff to buy.
http://www.dabs.com always seem to be pretty cheap for this sort of thing.
HTH!