I hate to tell you Mink Islander, but the one thing the govt has left out, besides the converter box you may need to update your antenna.
Antennas are designed for particular frequencies. They are fractions of the wavelength for the frequency. From my understanding there will be a few stations broadcasting HD on the VHF band. Most will be on up on the UHF band, so depending on your antenna and station your trying to reach maybe the issue.
So the best thing to do is hook up your hdtv and antenna and look at the channels in the coverage area and see what you can pick up. If some have moved off band then you may need to update the antenna and maybe add an amplifier.
some good sites to check out:
http://tvfool.com/
http://www.arrl.org/tis/info/catv-ch.html
http://antennaweb.org/aw/Welcome.aspx