yes a sky card with sky plus will work here in spain.
be careful if your card is part of a sky multiroom contract - sky dont like you taking the card to places where it shouldnt be, and letters will arrive, at the uk address where the card is registered, regarding your breach of the multiroom contract.
the number of channels you receive will be dependant on the sizre of your dish...80cm will get you about 50% of sky package channels.
for the free bbcs and itvs you will be looking at a dish size upwards of 1,4m, maybe 1.8m, or even 2,4m - expect to pay about 400, 700, 1200 repesctively for dish, stand, twin lnb and installation. they may be cheaper, if you can find them, but what about transportation costs!
do not go cheap and get a fortecstar 6 panel petal dish (sold by maplins). they are poor performers and have had some calls today from a few people whos fortecstar dishes have folded up on themselves in the winds.
netgears do work in spain, with most providers. if it does not you can get new wireless routers almost everywhere!
various broadband providers, telefonica (spains BT!), own and operate all the exchanges and most providers go through them. although at the end of the day best to see the local freebie newspapers as many telcos advertise special offers almost every week...and they try and discout the cost of calls to the UK...which may be useful to you.
hope this helps