You can buy a Slingbox, and connect that to your Router. I can watch Sky+ anywhere in the house, on my laptop etc via Wifi. I can also control it via my computers and laptop too.
However, if you cange a channel on your laptop / computer, then it changes on the box too, no good if someone is watching it on the main TV.
When I am also out and about I can watch Sky on my mobile or laptop. I just dial into my Slingbox using the net (or Three's mobile service). Great when I visit my parents in Austria.