I think he means that he wants to turn his pc into a receiver (i.e. control the channel changes).
DVB cards may get the job done...but it would take other stuff as well since DirectTV is an encrypted signal.
Do a google search on DVB sat cards.
or simply buy a $40 capture card from newegg and pump the receiver into the pc and record that way. It does make scheduled recording near impossible to coordinate though.
You can use Sage to do it. You will need a capture card and a IR transmitter. Sage can then control the IR transmitter to change the channel, and you run a S-video cable from your directTV box into you capture card.
There is no simple solution as of now. there are no cards that will act as the tuner for DirectTV- so if you're looking to record you're gonna have to use the tuner box itself and just capture the video stream using a capture card (like you would for capturing from a camcorder or VCR tape).
There is a way to use a capture card, coupled with an IR transmitter to record in a timer method- the computer triggering the Direct TV box to turn on/turn channels when commanded via IR at a specific time (similar to how you used to ahve to do it for recording from a VCR- you had an IR link which would turn on and start the VCR).
Now you can choose to capture analog stream via SVIDEO- or it might be possible to capture the direct MPEG stream off the box digitally - but you would need to get a SDI modification on the box to pass MPEG SDI- and then get a SDI capture card. If you're not interested in doing so- then you can get an analog capture device and use an app like Sage, as suggested above.