Capturing a cable signal

Hi all.

I'm a complete newb on this topic, so sorry for any stupid inquiries.

I'd like to be able to record approx 4 different local news channels...take the best video and info from each station on a given story, and then condense/summarize my own story out of it.

My local cable company won't let me grab the video from my dvr. I've done some reading on boxes like silicon dust's products but really don't know how or if they would work.

Any advice or pushes in the right direction to better understand what I'm trying to do would be appreciated.

Thanks-
Scott