Not sure what they are called but they allow you to watch sky in other rooms without an extra box.
 
In short how do  they actually work? Do I need an aerial socket in the additional room? I do have one but its in a really awkard place. Secondly are they any good?
 
There is one in argos for £40 but if that doesn't work then I might just bite the bullet and get an extra Sky box upstairs

You mean like the Digital sender/ recievers you can buy?

You have a link?

Theyre great, but if you have wireless internet or a microwave....dont buy one.  ive had a x sender for a yr or so now, microwave only interfears when on but wireless internet and digi senders do not mix, can only use one ata time, either or.  i bought a maguc eye from ebay for a fiver and some co ax and hard wired it, much bettter, is perfect picture all the time and carry the remote signal through the coax too.

All sounds like ball ache to be honest.
 
Cu3ed I'll post a link at lunchtime when Surf Control f**ks off
 
P.S Does anyone knwo how I can get round Surf Control in work. Proxies are disabled by the way