Thought I'd just share my finding with you all, in case anyone is actually interested.
Currently have a single PC conncted to ntl broadband via cabel modem. The modem connect(ed) to the PC via an ethernet 10base-t card I had plugged in.
Gonna get a new PC soon and mu kids are going to have this one. Wanted to be able to share the intrenet access so thought I'd investigate networking them up. the new PC will connect via ethernet cable (justlike this one used to do) and this PC, when it changes room will use a wireless card.
Thought I;d sort it all out sooner rather than later so bought a Linksys BEFW11S4 broadband router and a Linksys WMP11 PCI wireless network card.
Took out the old 10base-t card and replaced it with the WMP11. plugged thecable modem into the router via ethernet cable. Turned everything back on, had to insert a CD for driver installation when the hardware was auto-detected by Windows XP Pro and then, voila, had the same internet access as I did twenty minutes before when connected directly.
Aboslute piece of piss, this wireless networking!!
In the first ten minutes (follwing a little reading previously) I even had the router forward all http traffic to my specific (the only one at the moment) PCs Ip address so when I fire up my web server it finds my PC rather than any others.
So, the bottom line I wish to share with anyone thinking of doing the same, don't hesitate. Plugged in and worked first time

I can thoroughly recommend (so far anyway) Linksys for sharing ntl cable modem connections. Forget the more expensive "NTL cable modem sharing" kits you can buy.
Sorry if I've bored you. I'm chuffed with the easy setup and just wanted to share... so flame away ...