Comcast/Mythtv (OT?)

[bogstad-e+AXbWqSrlAAvxtiuMwx3w at public.gmane.org (Bill Bogstad)]

This is slightly off-topic, but does involve Linux...

I've got a KnoppMyth Linux system running with two analog tuners
connected to my Comcast cable with a MediaMVP settop box for display
purposes.  The whole thing has a good WAF (Wife Acceptance Factor).
Unfortunately something in my latest Comcast bill is worrying.
Starting soon (end of the year?), they will have new cheap Digital
only TV feeds
which are considerably cheaper then the current full analog feed.
They also say they will no longer accept new customers for their
'Standard Cable' (full analog feed) at the
same time.  My worry is that this is a sign that they want to get rid
of their analog feed entirely which will break my current setup.  I
don't currently have a QAM tuner so
I have no idea what channels are available as unencrypted digital, but
my guess from web surfing is not many.

My questions are:

* If you have a QAM tuner on Comcast in the local area (Cambridge
would be best), what channels do you see in the clear?

* I believe that Comcast has switched all digital in other parts of
the country.  Anybody with experience/insight into how long my current
setup will be grandfathered in?

* What are my options for encrypted QAM and Mythtv?  (Note: I'm
currently SD only and HD would be nice, but not a requirement.)

* Anybody else see this insert in their Comcast bill?  Is this the
whole area or just a Cambridge thing?

Thanks,
Bill Bogstad