There are no monthly fees to pay to receive Sky TV via satellite. Beware of people selling microwave systems as these are illegal - often you'll be required to pay a yearly fee in advance which is never a good sign. With a satellite dish and Freesat card (included with the apartment) you have no fees to pay at all.

Because of the nature of satellite reception in the south of Spain, not all channels are available at all times. The following channels are very reliable and I've never a problem with them (correct as of 11 Oct 2007):

BBC1
ITV
Channel 4
Five Life
Five US
Sky News
Bloomberg
BBC Parliament
Euronews
Al Jazeera (English)
Russia Today
France 24
Film 4
Men & Motors

The following channels break-up at certain times of the day, but overall reliability is about 80%:

Channel 5
BBC2
BBC3
BBC4
ITV2
ITV3
ITV4
Sky Three
BBC News 24