Cable Forum - ICS through Telewest Broadband

Hi guys

Sorry if this is in the wrong forum, first post newbie here :o:

I'm after a bit of advice on how to setup ICS on Telewest Broadband so I can connect an Xbox 360 to it. Currently he (my Brother) has the Cable Modem connected to his PC via USB and the 360 connected to the Modem via Ethernet. At the moment if he wants to connect to Live he can only do this if the PC is switched off or not using the internet connection and vice versa. I want to set up ICS for him so he can connect to both at the same time. I've had a look on the Network Connection Settings and I can't see anything that relates to sharing the connection?
I've been told that he'll need two NIC's. One to connect to the Modem and the other to connect to the Xbox via crossover cable. This makes sense, but I'm still sceptical on how this would enable the option to share the internet connection? I told him it would be easier to buy a router, but he's a bit tight with his money (tight meaning he has none :D)
I've been looking everywhere on the net for answers, but it's all conflicting information. If anyone could help and talk me through how to do this it would be much appreciated ;)