Telephone & Addresses

Telephone

Websites

All Area Codes - Look up U.S. and Canadian area codes. 
AnyWho - Find phone numbers for people and businesses or do a reverse lookup to find a business or person by their phone number.
Internet 800 Directory - Directory of toll free 800, 866, 877, and 888 phone numbers.
Superpages - Find businesses and people.
Switchboard.com - Yellow pages, white pages, area and zip codes, maps, and more.

Addresses

Websites

Calculate Postage - Calculate domestic, international, and business postage.
Locate a Post Office - Find post office locations, automated postal centers, and locations to buy stamps.
ZIP Code Lookup - Find zip codes by address, city, and company or find all cities in a zip code.