Well, it's a *smidge* of a grey area
Have a look on AV Forums, but basically I'm using a Dreambox to read the $ky card and run a (local only) card server. This is read by Acamd on the HTPC which plugs in to DVBLink TV Source - a virtual tuner interface for MCE. It's come on leaps and bounds in the last few months and is now pretty stable. This is the only way to watch Sky HD in MCE as the Dragon CAMS don't work with the new white card.
Before anyone leaps on me from a great height, this info is freely available on AVF and they have a hella strict policy on naughty stuff. None of this would be an issue if Murdoch actually complied with the EU regulations and provided a legitimate CAM but hey ho. I'll understand if there's a need to delete this post though!