Offered by AT&T, this site allows you to search white pages, yellow pages, toll free numbers, or do a reverse look-up by telephone number. 
 

The Area Decoder :  http://decoder.americom.com

Type in a city to find the area code, or type in an area code to find what cities it includes. 
 

Infobel World Telephone Directories :  http://www.infobel.com/teldir/default.asp

Contains over 400 links to yellow pages, white pages, business directories, e-mail addresses, and fax listings from over 170 countries around the world. 
 

InfoSpace.com :  http://www.infospace.com

Includes yellow pages, white pages, and reverse look-up by telephone number or address.. 
 

International White and Yellow Pages :  http://www.wayp.com

An international index of white, yellow, or fax directories, this site is useful for finding phone numbers from around the world. 
 

Reverse Phone Directory :  http://reversephonedirectory.com

A collection of online reverse telephone books searchable by address or telephone number. 
 

Switchboard :  http://www.switchboard.com

Switchboard is a nationwide business and residential directory. 
 

The Ultimates :  http://www.theultimates.com

Offers white pages, yellow pages, e-mail directories, and trip planners.  The Ultimates places multiple versions of these resources together on one page for convenient searching. 
 

WhitePages.com :  http://www.whitepages.com

Includes business and residential look-ups, as well as a reverse directory by address or telephone number.