So far as I am aware you can get new deals as any new customer would – the only thing is that you may have to get somebody in to do your connection privately (the guy that knows our block is Alan Kay and I think his details are in a related thread regarding Sky at http://www.rainbowquay.co.uk/Forum/index.php?topic=9.0)
The terms of our lease do not allow individual dishes to be installed but there are communal dishes on each block.
In order to use Sky+ you need two signal feeds – you can achieve this through two means:
1. if you have a 2nd feed in a bedroom you can have that cabling moved through into your lounge
2. you may be able to get a signal splitter (or stacker) installed on your lounge feed which basically turns it into two signals somehow on top of each other – I have this in my flat and have not had any issues with it over the past 4 or so years.
I am not sure how multi-room works (I have one of those gadgets that transmits the signal from my lounge into a bedroom and it works pretty well).
I hope that helps – give us a shout if you have any (non-technical!) questions.