Hey Michael:
Check out these sites for good tips on your subject:
http://www.digitalfaq.com/
http://www.tv-cards.com/
Does your video card in your PC have a video input? Most video cards that I have seen only have either an RCA input or an S-video input. This would only allow for analog transfers. Unless there is a way to copy the video file directly from the PVR to the PC hard disk. Maybe someone can chime in with that information.
As for editing out commercials from MPEG2 files I found Womble MPEG2VCR the best and easiest program for this. It is not free though...but there is a trial version that you can try.