Broadcast HD channels over cable

Hi All:
I currently receive local broadcast HD channels thru a comcast set top
box on my tvs.
I recently read the following on the comcast site:

"If I have a digital-cable-ready HDTV set, do I need a CableCARD or
special HD set-top box to view HD programming?

Digital-cable-ready HDTV sets that are now available have built-in HD
capability so no special set-top box is required to recieve HD signals for
broadcast channels.
When used with a CableCARD, these TV sets will receive any Comcast digital
cable channels that you currently subscribe to (e.g. ESPN, HBO, or Showtime).
"

If no set top box is needed to receive HD broadcast channels on HD TV's,
does that mean I can use the ATI TV Wonder 650 tuner which has both Analog
and Digital tuners to receive the same HD broadcast channels on my PC with
Vista (or my Media Center 2005 PC)?

This is what the ATI 650 tuner description says: " HDTV with No Monthly Fees
HDTVEnjoy “free-to-air� HDTV or unencrypted ClearQAM digital cable
programming and see your favorite TV shows and sports programs in stunning,
true-to-life, high definition. As “free-to-air� HDTV (ATSC in North America)
is not burdened by monthly fees, watch with pleasure while avoiding the pain
of incurring any charges."

If the cable company transmits the HD broadcast channels unencrypted and no
set top box is needed, will I be able to receive those channels with Vista
Home Premium? If not, why wouldn't Vista permit that function?
My Vista pc currently recognizes that I have a wide-screen monitor and the
tv window is in widescreen format but I have an analog signal so the picture
only fills part of the screen and if I zoom the picture to fill the screen
the picture is not very good. It doesn't seem logical that the latest
operating system won't allow "free over-the-air content" to be viewed on the
pc via an unencrypted cable signal when the government wants it, the cable
company doesn't care and the pc owners want and need it to even
satisfactorily utilize the tv tuner on a pc once the standard changes to a
widescreen format in the not to distant future!

xiowan...........in tucson