If you go to the Silicon Dust Website (they make the Hdhomerun) there is a wiki with QAM listings. The only hitch is that it's not tied to a particular provider so if there are multiple cable providers in your zip code, it won't differentiate.
Zahnrosen:I'm trying to figure out if clear QAM is available in the 30115 zipcode on Comcast's network. Whats the best way to verify this before I buy QAM hardware?