Woops, I got brainwashed into associating sling with Foster City.
Anyway, you can go on antennaweb.org and enter your zip code.
http://www.antennaweb.org/aw/Address.aspx
It will give you a list of all the channels with their physical and display/virtual channel #s.
For analog TV, the physical channel # is the same as the display #.
For digital TV, there is a physical channel # and then there is usually meta-data called PSIP, a portion of which provides a "display/virtual" channel #. If the PSIP is missing, then the virtual channel # is the same as the physical channel #.
For many UI you can use the physical or the virtual channel # to tune, so if NBC is normally display/virtual 4-1 but the physical channel is UHF 48, you could enter 4 or 48 and it should go to the same channel.
It looks like on the setup screens DTVPal only takes the physical channel #s and doesn't give an indication (on those screens) of what the virtual channel #s are.
On the antennaweb.org site, the "channel" is the display/virtual channel # and the "frequency assignment" is the physical channel #. It also indicates UHF or VHF in the first column so you can see which type of antenna will be more appropriate. If you are in an area with strong signal with little multipath (not too many tall buildings or mountains) most reasonable antennas will pick up all the UHF and VHF channels.\\
Big thanks for taking the time to run through the product and giving us a taste.