Hi mate, it is possible but as far as i know you still need to use the NTL box. IE you cant scan the NTL channels with a TV card as the signal is encrypted.
They way ive got it setup is, ive got a SCART > svideo and Left + Right Audio channels converter block (cheap about £3on the bay) plugged into back of NTL reciever. Got an svideo cable from the block to the TV Card (i use Wintv PCI Theatre). Got the 2 audio leads into a single 3.5mm jack which then plugs into TV card.
Hey presto NTL on your PC.
Ill get some pics tomorrow if you want?