This is the old school way of giving yourself multiroom (without paying sky £10 a month) - allows you to control the TV via another IR controller. Obviously you have to watch the same channel though!
The best I have seen for these or similar on the high street is about £10, or £20 inc new controller. However, I have had one of these for a few months now and it does a great job.
Here's what the blurb says:
Tv Remote Control Extender - Watch and control digital satellite from any TV
The SLx Link simply plugs into the digital coaxial cable where it enters the second TV
and extends remote control back to the Satellite box.
Once the SLx Link is in place you can control the Satellite box
with the original remote or a suitable universal remote control
The SLXLINK system is the easy way to distribute high quality digital pictures plus normal off air channels around the house, and control the digital satellite receiver from the any other room.
SLXLINK uses the tvLINK function built within the Sky digital receiver to control the digital receiver from a different room.
The SLXLINK eye sits on top of the TV in your bedroom or other remote viewing point. It sends the remote control signals from the bedroom to the Sky digital receiver in the living room via the same coaxial cable that is delivering the Sky pictures to the television.
The SLX Link works by picking up the remote control signal from your Sky remote in your bedroom via the little eye, converting the infra red pulses to electronic pulses, sending the electronic pulses down the cable to the Sky receiver. The receiver will accept the electronic pulses only at RF out 2 and they then pass through the same circuit as the remote receiver eye that is on the front of your digibox.
Whoops! Forgot to include carriage (though you can collect from one of many sites):
Basildon, Brighton, Bristol, Burgess Hill, Cardiff, Coulsdon, Crawley, Croydon, Eastbourne, Enfield, Exeter, Guildford, Maidstone, Medway, Merton, Oxford, Penge, Portsmouth, Slough, Southampton, Swansea, Swindon, Tunbridge Wells,
£4.31 if you collect, £8.45 if you don't (though postage appears to be constant regardless of number you purchase)