If you're going for FreeSat, you just need a dish (it could be any dish, even an ex-Sky dish) and then buy the box.
If you have an unused Sky dish and box, you can phone Sky and ask them for a FreeSat card, which goes into your Sky box and turns it into FreeSat. But you will only get FreeSat channels, nothing else.
Not many TVs come with FreeSat built in, more TVs come with Freeview. But yes, if you have a Freesat TV and a dish, just connect them up.
I have freesat and the EPG isn't as good as Freeview as it doesn't show your current channel in the little box in the corner like freeview does.
This is down to the box you use, not the signal provider.
This is one reason the Sky boxes are pants, because you don't get the little picture in the corner while in the EPG.
For example, Humax (who also make the YouView box) make both Freeview and FreeSat boxes, they both have a essentially the same EPG with the little picture in the corner.
If you don't like your EPG, get another box from another maker.
