It even has a toll free lookup. What is neat about it is the government listings. WhoWhere has all those hard to find government phone numbers as well as the names of the officials. Nice phone directory that goes far beyond. It has a categorical look up for businesses.
Switchboard is also a good mix between a map and a phone book.
You can put in an address and then look at business that are close to that address. For example, If you are staying in a hotel in Dallas you could put in the address of your hotel, then see what restaurants are close to the hotel. It doesn't just limit you to restaurants but a wide variety of business categories. The yellow pages on the Internet. Business listings only.