It's too bad there's still so much mystery about getting HDTV tuners for PCs. It could be really easy if they tried.
Almost all the shows on ABC, NBC, CBS, PBS, FOX, WB, and whatever became of the UPN stations from 7pm-11pm are HDTV.
You can get an HDTV tuner for your PC for $99 *if* you have an ATI card with MPEG-2 decoder (most do) or a fast enough processor to do software decoding. Alternately you can get an HDTV tuner with on-board decoder for about $189. Add component video out (to drive an HDTV) for another $60-80 either as a daughter card or built in depending on model. There are several models out there.
I'd love to just get the $99 one but I don't want an ATI video card because of the free bonus feature it comes with: ATI Driver Nightmare Platinum Edition.