I am not sure I understood your question.
If your setup is like this:
Cable/Antenna -> TV Tuner device connected to PC (either in PCI slot, or USB) -> Output to monitor or TV set from PC
then you can tune to a channel using remote control, and can schedule MC to record a channel at specified time.
If your setup is like this, on the other hand:
Cable/Satellite dish -> Cable/satellite set-top box -> (via Composite video or S-Video) to capture card in PC -> output
then you can not control channel switching from inside of MC, and can not do scheduled recording.