You'll need something from this page:
http://grax.co.uk/P/Sky-Compatible-Indoor-AmplifiersDistribution(S19).aspx
The exact product you'll need depends on current and future plans but if you're planning on eventually supplying signals to the entire house then this:
http://grax.co.uk/P/TRIAX-621-Domestic-Distribution-Unit(945).aspx
is the dogs danglies.
Whichever system you chhose will require some additional accessories though. You'll need Diplexing or Triplexing wall plates to decombine the signals at the outlet.
For maximum flexibility, the Triax DDU should be installed in a central location. Then run 4 cables from the location where a satellite dish would be fitted to the DDU. Run 1 cable from the TV aerial, 1 from the DAB aerial and 1 cable from the FM aerial, all to the DDU. If you have CCTV with an RF modulator you can also run a cable from thi to the DDU.
You now run 4 cables from the DDU to the main TV location and 3 cables from every other TV location to the DDU. Note that not all of these cables are likely to be used but they allow for future options.
You will now be able to have Terrestrial TV, FM, DAB and CCTV at every TV point. Also, if you have Sky at your main TV point you can send the picture round the house via RF. You have the option of Sky, Sky+ or Sky+ HD at the main location with additional standard Sky subscriptions in up to 2 other locations OR an additional Sky+ or Sky+HD subscription at 1 additional location. Any more than this and you'd need to run additional cables from the satellite dish directly to the additional TV locations. Note, Sky subscriptions wouldn't actually be required. Freesat is also available.
Of course, your other option would be to use CAT5 distribution but this is considerably more costly and complex although it would allow you, for example, to fit a HD receiver under the stairs and pipe the HD signal to TV's around the house thus meaning you simply have a TV floating on the wall with no boxes nearby.
Like I say though, costly and complex.