DVB-S cards can use smart cards to get premium (encrypted) channels as long as you have a subscription. They don't lock you out like cable does.
Unfortunately for American viewers, there is no legal way to do this. Although DVB-S is an international standard and widely adopted, current laws within the US prohibit using off the shelf hardware to decrypt the video signal. Doing this is considered signal theft.
Dish Network uses Nagra 3 encryption, as do some other providers in Europe. There are no legal conditional access modules available for this crypto system, so any use of these smart cards in devices other than what the provider supplies is considered theft, as well as a violation of the DMCA.
DirectTV uses it's own proprietary system and can only be legally used with their hardware.
It really sucks paying to loose control.