If you are looking for a details on all of the stations in a market try www.radiostationworld.com You can then select a state and market and get details of all of the channels in a market. There are also links to the FCC information for each station including estimated coverage maps.
We have that as well here, except no coverage maps yet. But you can see all your market stations on a google map with heading and distance to each tower: http://hdtvmagazine.com/programming/broadcast.php