If you haven't seen the ads on TV, the US is switching to a digital broadcasting standard (ATSC) for over-the air transmission In Feb 2009. This transition from the current standard(NTSC) has been in the works for a couple years now, and in Feb 2009, the TV stations have to broadcast in the digital mode ONLY. This only affects people receiving TV signals with an outside antenna - as of right now, the cable/satellite companies do not have to make any changes.
All the Pioneer TV tuners are the NTSC system, which means in a little over a year, there will not be any stations transmitting a signal that they could receive. To the best of my knowledge, none of the car audio companies have come up with an ATSC tuner that works very well in the mobile enviroment. That may change, but I understand it is a lot more difficult to do it with the new system.