MCE doesn't support DVB-C, though I dare say there are cards out there that will appear to MCE as DVB-T.
Depending on how you deal with the subscription element of Virgin, and legal interpretation you'll also at best be breaking your Ts&Cs with Virgin, and at worst be breaking the law.
MCE2005 (Reluctantly decided not to upgrade to TV Pack - will see if 7MC fixes the issues) | AMD64X2 3600+ | 1Gb Ram | 3x500Gb SATA | Hauppauge PVR150 | nVidia 7300LE silent GPU | Pig ugly big black case | Virgin Media cable | Xbox 360 wired extender