Cable and DISH TV users don’t have to worry. Neither cable or dishes use analog tuners, nor digital tuners. Those tuners are called QAM.So the cable or dish companies will simply take the digital signals and downcovert them if needed, and send them to you.
Antennas work with analog signals (called NTSC) or digtial. The original plan did not call for moving TV out of VHF, it originally called for moving TV from Channel 7 thru Channel 51. Later broadcasters wanted to keep Channels 2-6 because they cost a lot less to broadcast on and the range is further. Although they are subject to more intereference it was thought that technology would compensate for that. It has helped a bit but not much.
I did a bunch more Yahooing and Googling and found this site
Rules For Sales of TV after March 1, 2007
It appears the TVs will be allowed to be sold as long as they do not cross state lines. This applies to Internet sales as well as shipping from out of state distribution centers.