Good question. I guess it depends on how much money you have burning a
hole in your pocket.
Obviously you need some bandwidth to move decent video over and I'm
guessing granny doesn't have ADSL, so there's your first hurdle.
If it's going to be running all day, it'll burn a fair hole in grannies
eletric bill, so there's a second hurdle.
You'd probably want a kill switch on it from your end as you don't
really want to be feeding video across the net 24x7 cause your ISP will
probably slap you.
I'd say from grannies end, you probably want something that has a TV out
so that you can just tell granny to turn to channel X. With that in
mind, if granny has Virgin Media, you can probably get a cable modem
dirt cheap or just borrow a neighbours wifi (I mean by asking :-)
they're fairly generous when it comes to helping their elders out.
If you're buying new hardware, something low power would be good. Think
MiniITX/LEX/MacMini/whatever. Something fanless and with CF instead of
HDD would be good since it tends not to make a noise.
Make sure you power cycle it in situ and that it comes back OK all by
itself. You don't want a 1000 mile round trip every time there's a
dropout.
That's just my 2p. Hope it helps.
BOfH.