Stumbled across this site the other day:
While the main page provides a list of major US cities, plugging in a specific ZIP code into the search box breaks out an area. I used it to check two in my hometown (Fresno CA) in areas that I don't get to much and was surprised at the number of little places I'd never heard of.
Click on the Restaurants link in the left margin to bring up just those businesses. Another nice feature is that below in the left margin it will list other small towns in the vicinity.
Naturally, there will be some listings that are no longer valid and new ventures that aren't included, but I was pleasantly surprised at how current it is.