No, you cannot use the TV tuner built in on Sky digibox equipped area. That means you will still need sky digibox per TV.
and NO, your digibox is charged per month and is not free.
on the new anti piracy area of sky, you will not be able to watch all channels if you connect the coax direct to the TV. and that is only for now, once they activate the system, subs will be required to get a digibox 100% in able to watch sky cable.
and lastly... picture quality on sky using lcd is still not at par with Cignal TV digital broadcast.
unless you get the HD package which they charge alot.