Splitters are the shiznit... It should work ok with computers. Which leads me to my next question... What kind of wiring do you need on your CPU to connect to the cable jack on the wall? The same one for normal TVs?
I would assume Radio Shack has them but I know Now Audio Video does. (Now Audio Video is closer to my house then Radio Shack is, that the only reason I went there for help over Radio Shack) When you get a TV Tuner card on it there should be a COAX outlet just like your TV and you plug in the normal COAX cable into it just like it was a TV.
I have one of those 3 into 1 splitters from Time Warner. One for RR and two for TV's. No problems except Ch. 2 (Ch. 51).
I would think you could do it. I have done it on old my RR connection before. They probably don't want you using a router so you have to pay for the extra IP's.