You have 2 options:
1) EASY: Cable modem -> uplink on hub -> 2 computers
Only problem is if you want both computers to access the Internet - you only have one IP address assigned from your cable provider and you cannot use the same address for both computers. For a few bucks a month, @Home allows you to sign up for a second IP address for your second computer (I'm sure most cable providers have this service). The nice thing about that is you don't have to set up a proxy server, and only one computer has to be on at a time (both computers have a direct connection through your hub).
2) HARDER: The other way to connect 2 computers is to have 2 network cards in one computer (one connecting to the cable modem, the other connecting to the other computer). Then you have to set up proxy server software on the PC with 2 NICs. This method is free, though.
Hope this makes sense.