basically, all it is is a kind of tranmitter receiver system, that beams the signal from one place to another.
but unlike the wireless type you can buy, this does it via the internet.
so you can have a sky box in the uk (connected to a slingbox tranmitter which is in turn connected to your broadband connection) , and watch the output on you tv in spain (via a slingbox reciver connected to broadband,)
it is a neat toy, but ....
some of the uploads speeds can make the picture not as clear as it should
its not worth it is you have upload / fddownlaod quotas on you r net usage.
you still need a sky subscription to watch sky pay channels.
you will have to watch the same channels as being viewed on the tranmitting sky box / slingbox.