If you have an Amplifier or Cinema System - that will allow you to listen to normal TV through all of your speakers - it will process the sound. Unless the broadcast is in 5.1 surround sound (very few are) you will get processed NICAM stereo or Dolby Stereo. It will still sound good but the effects of 5.1 surround sound wont be there watching Coronation Street
Buy a scart lead that is fully wired and pref Gold plated but I have excellant sound from the regular scart leads.
i have a cheap surround system ( �50 from asda ) and i can listen to sky through it. i just select the function ( or aux as on my old one ) to listen to sky.