Postal Information in the Yahoo! Directory

USZip.com
Instant ZIP code search including U.S. census data that can be searched by ZIP code or city name.
www.uszip.com
National Address Server
Enter a partial U.S. postal address and the server attempts to rewrite the address in the proper format along with the ZIP+4 code.
www.cedar.buffalo.edu/adserv.html
Canada Post Corporation@
dir.yahoo.com/.../Agencies/Canada_Post_Corporation
Postage Rate Calculator
Calculate domestic or international postage with this tool from the U.S. Postal Service. Select your mail's destination, shape, size, and weight to get a postage quote. Also includes a ZIP code lookup.
ircalc.usps.gov
Zip-Code-Database.Org
Find ZIP codes and postal information for all 50 U.S. States. Includes ZIP code search by city and by area code.
www.zip-code-database.org
National Address and ZIP+4 Browser
ZIP code finder for addresses in the U.S., showing nearby addresses, similarly spelled streets and cities, and a list of standard address abbreviations.
www.semaphorecorp.com/cgi/form.html
Jay Computer Services: ZIP and Area Codes
ZIP code and area code lookup and conversion database. Includes reverse area code lookup and Canadian postal codes.
www.jcsm.com
U.S. State Abbreviations (13)
dir.yahoo.com/.../Postal_Information/U_S__State_Abbreviations
Postal Rates.info
Guide to to postal authorities, post and ZIP codes, stamps, and philately around the world.
www.postalrates.info
ZIP Codes and Postal Codes of the World
Gives links to postcodes and ZIP codes by nation, post office home pages, and other addressing and postal information. From EmbassyWorld.com.
www.embassyworld.com/data/Zip_Codes.html
USPS Postal Rates
Information about postage rates for domestic, international, and business mail from the U.S. Postal Service. Includes links to online postage rate calculators.
www.usps.com/tools/calculatepostage/welcome.htm
Addresses.com: ZIP Code Lookup
Find ZIP codes by United States city or state, or use the reverse ZIP code locator to find what location corresponds to a given ZIP code.
zipcodes.addresses.com/zip_code_lookup.php
Area Codes - Zip Codes
Look up U.S. area codes and ZIP codes, or find postal and phone information for a town, city, or county.
www.area-codes.com
Wikipedia: ZIP Code
Encyclopedia article about the history and uses of the United States postal codes. Also includes lists of zip codes by state and postal codes by country.
en.wikipedia.org/wiki/Zip_code
Conversion of German ZIP Codes
www.informatik.uni-frankfurt.de/plz/plzrequest.uk.html
ZipDecode
Java-based map of the continental U.S. that progressively narrows down the area covered by a ZIP code as you type in the numbers one by one.
acg.media.mit.edu/people/fry/zipdecode
USAZipInfo.com
Provides lists of ZIP codes by state, city, county, and area code.
www.usazipinfo.com
ZIP Code Look-Up and Address Information
Find the ZIP code for a given address, search by city or company, or find all cities in a ZIP code. From the U.S. Postal Service.
zip4.usps.com/zip4
Philippines Zip Codes
Browsable list of Metro Manila and provincial zip codes.
www.globalpinoy.com/infocenter/zipcodes
ZIP Code Distance and Radius Search
Find the distance between two ZIP codes or find all the ZIP codes within a given radius.
www.zipcodedownload.com/Lookup