I currently have a Motorola SB4100 connected to my PC via the USB ports (This is my NTL Internet connection).

What i want to do is connect a wirless router (Recommended by NTL) between the Motorla and the PC, so that i can connect another PC wirelessly to the internet.

Does anyone have any idea if this is possible, i have ran through the installation instructions and it says to connect everything using Ethernet cables.

The problem i have is that i don't have a network card in my PC (but i can get one) is it possible to do this leaving my existing USB connection and connection the hub to the Modem via one ethernet cable.

Hi. Im unfamiliar with NTL and thier modems so excuse any rubbish i may say here.
If you want to share the net with more than one PC and over wireless, you should eBay for a Wireless Modem Router. That would replace the current Motorola modem (but still allow you to input the NTL settings to keep connected to NTL), give you a wireless gateway for you're wireless internet connection and lastly a router for wired ethernet internet connection.
I dont quite understand what you mean with you're hub though ?

It is possible but you have to get a network card put in your PC or get an USB network adaptor. Otherwise it is waste of time to try install a wireless router.