Basically yes.

The bog standard Sky Digibox has red / white / yellow sound outputs so simply pump that into a spare channel on your amp (hopefully something like TV/DBS) and click ProLogic and you will have your amp make Dolby ProLogic sound from the Nicam signal it receives from the Digibox.

TEASER : If you upgrade your amp to a DolbyDigital one and spalsh the cash on a Sky+ box you will get stereo sound through your rear speakers (i.e. Dolby Digital)- this doesn't seem much but it sounds absolutly amazing in reality ! You also, of course, get the full digital recording, live pause PVR facilities which are well worth the cost.