How about just run a composite (RCA) or S-Video cable from your digital cable box right into your TV tuner? You should be able to record from rca or s-video inputs. And if you take the line coming out of the wall right into your tv-tuner, it will be regular analog cable. In delaware, we have comcast, and I had digital cable for a month, and I hated it! The quality was no were near as good as it looked in the store were I bought my TV, but for HDTV stations (only like 3 though) it was amazing. But since there was only three HDTV stations, I got rid of it, and got DirecTV. And let me tell you, I have it on my 48'' Mitsubishi HDTV (through S-Video), my 19'' 10 year old RCA TV (through regular coax cable), and my Pinnacle PCTV PCI card (S-Video) is shared with my 13'' Sharp TV (through composite RCA). They all look amazing!
-Josh