jhaime,
what mrplow said isn''t wrong, but it's not what you would want to achieve. He's right in that all payTV providers want their customers to use only certified equipment, which in most cases is has fewer and/or crippled functions (like being able to record). This does not mean that it's not possible to use other equipment!
Be aware that using non-certified devices may be a breach of the T&C of your contract with the provider, but it's not "illegal", and no one on the "other end" is able to determine in which device(s) you use your smartcard. The most severe sanction if you're "cuaght" (which is highly unlikely) would be a termination of your contract.
I'm located in Germany and have a Sky (Germany; used to be "premiere") subsription; by using an eyeTV hybrid (DVB-C) and a Terratec USB CI with an Alphacrypt CAM, I was able to replace my receiver and record in native quality on my Mac.
Here's a brief rundown on your options, if you are a payTV subscriber and want to watch/record encrypted channels on your Mac. Basically, there are two ways:
1. Get an eyeTV compatible device (there are other solutions, but the eyeTV software is far superior) with AV-inputs and feed your receiver's output not to the TV, but to the eyeTV device (let's call it eyeTV for short).
Pros: no hassle with CAM and CI (see below for more on this); simply use your subscription as before, but be able to record any show from your receiver on your Mac, without any artificial restrictions or expensive crippled equipment from your payTV provider.
Cons: You need to control two devices (choose the channel on the receiver, control the recording with eyeTV), and, maybe more important, strictly speaking you don't receive TV, but simply the receiver's output, so you don't benefit from multiple sound tracks or get Dolby Digital etc. (or HD, for that matter).
This is what mrplow recommended, but there's a far better way:
2. Use eyeTV hybrid or a Terratec H7 (DVB-C) or eyeTV Sat (you didn't state if you're on cable or use a satellite dish, so I give both ways). Both the Sat and the Terratec have a CAM slot, in which you put a CI, in which (bear with me ;-) you put your payTV smartcard. For the eyeTV hybrid you need an external CI in which to put the CAM with the card (like the Terratec USB CI).
Cons: Need to handle some technical stuff, like getting to know what a CAM and a CI does etc.; sometimes, not fot the faint at heart ( but once your setup works, simply forget this stuff ;-)
Pros: Watch/record encrypted channels in pristine quality (I always wanted to use that phrase, but it's really appropriate here! picture quality is so much better than feeding through an analog input)), enjoy Dolby Digital (and, if your subscription offers it, HD; make sure your Mac is powerful enough), and of course for the eyeTV software this now is TV, as opposed to a video feed in scenario #1, so you can switch channels etc. directly in eyeTV. (Also get rid of enforced age verification for good, by changing the treshold setting on the smart card; don't know if this applies with Sky UK)
Summary: As you might have guessed, I recommend scenario #1, if you really want to see your monthly's subscription worth in picture & sound quality.
If you need more info or have questions on using eyeTV for payTV and in general, I recommend the eyeTV lounge:
EyeTV Lounge • Index page
Hope this was helpful. If you have any questions, don't hesitate to contact me.
Regards