This site may be helpful:

http://www.practicallynetworked.com/sharing/sharingcable.htm

>Hi All,
>
>I've just finished setting up a lan in my home with the express purpose of being able to share my cable modem connection to the internet with a second pc(cable modem both ways, no dial-up).
>
>Has anyone had experience with the software necessary to allow multilple simultaneous users.
>
>I'd appreciate any advice, url's to web sites, etc. etc.
>
>TIA
>
>Jim Harvey
>jeh@gscyclone.com