Links to Post Office Pages
Links and resources for postal code and international address and address format data.
http://www.grcdi.nl/linkspo.htm

Postage rates worldwide
Directory of mail rates (domestic and international letter rates) with links to the rate calculators or rate tables of postal services in most countries of the world. email rate queries supported.
http://www.geocities.com/wallstreet/exchange/1161/

National Address and ZIP+4 Browser
Interactively browse all address and ZIP+4 records in the United States.
http://www.semaphorecorp.com/cgi/form.html

SpeedKeys.com
SpeedKeys is a fast and easy zip code, city, state and area code look-up program. It can also generate an optional PostNET Barcode.
http://www.speedkeys.com

ZIP Code Lookup
Lets you get a list of all ZIP codes in a city, county, or area code.
http://www.getzips.com/zip.htm

Simply Zip Codes
ZIP code, city/state, area code lookup along with distance calculations and population data.
http://www.simplyzipcodes.com

PostalRates.info
Postal rates, post codes, philately and Postal Authorities around the world.
http://www.postalrates.info

KJL Software, Inc.
Databases of US ZIP Code and Area Code information.
http://www.kjlsoftware.com/

International Mailing Address Formats
Includes format information and/or examples for many countries, and links to additional references.
http://www.bitboost.com/ref/international-address-formats.html

DirectMailQuotes LLC
Zip code directory lookup as well as postal rates, regulations, glossary of mailing terms.
http://www.directmailquotes.com/postalregs/index.cfm

ZIPFind's Postal Code Calculator and Data
Calculate distance in miles between two ZIP Codes. Find all ZIP Codes within a radius of a ZIP Code.
http://www.zipfind.net/

Free ZIP Code Lookup
Free zipcode lookup with areacode, county, latitude, longitude, MSA, PMSA, congressional district, FIPS code, and timezone. Updated monthly.
http://zipinfo.com/search/zipcode.htm

Canada Post: Postal Code Lookup
Look up postal codes for any address in Canada. Also look up address ranges for given postal codes.
http://www.canadapost.ca/personal/tools/pcl/bin/default-e.asp

zipdecode
Java applet which maps United States zip codes on a map, reducing possible matches as the number is typed.
http://acg.media.mit.edu/people/fry/zipdecode/

Zip-codes.com
United States. Includes some statistics and histories of the post office and of the development of the ZIP (zone improvement plan).
http://www.zip-codes.com/

United States Postal Service: Zip Code Lookup
Find the postal code for a United States address.
http://zip4.usps.com/zip4/

The National Address Server
Translates valid U.S. postal addresses to the proper format along with the ZIP+4 code.
http://www.cedar.buffalo.edu/adserv.html

AskYP - Zip Codes
Find zip code by city and state and find city and state by zip codes.
http://www.askyp.com/Zipcode/

Australia Postal Codes
Offers postal codes search by location and state.
http://www1.auspost.com.au/postcodes/

Belgium - Postal Codes
List of Postal Codes and its corresponding city.
http://www.charline.be/info/codepost/cpost.htm

Canada - Postal Code
Find Postal Code by street address, municipality and province.
http://www.canadapost.ca/tools/pcl/bin/advanced-e.asp

China Zip Codes and Area Codes
Offers Zip codes and area codes of major cities in China.
http://www.travelchinaguide.com/essential/area_zip/

Danmark Postal Codes
Find zip codes from street address and locations.
http://www.postdanmark.dk/contentfull.dk?lang=en

France - Postal Codes
Offers zip codes search.
http://www.laposte.fr/sna/rubrique.php3?id_rubrique=59

German Postal Code Lookup
Look up postal codes, the German equivalent of U.S. zip codes, for any German address.
http://www.bitboost.com/ref/international-address-formats/germany/plz-en.html

India - Postal Codes
Search for Postal Index Number PIN Code for the specified Locations.
http://www.mapsofindia.com/pincode/

USPS - ZIP Code Lookup
Look up a zip code by address, city and State.
http://zip4.usps.com/zip4/welcome.jsp

US Zip and Area codes
Structured and mapped list of states, counties and cities within the United States. Corresponding information like zip, area, FIPS codes.
http://www.zip-area.com

Find A Zip
A detailed database of all US Zip Codes, City Information and Area Codes.
http://www.findazip.com

Zip Codes Directory
Provides search for ZIP and area codes for a city.
http://www.1zipcodes.com

US Zip Code
Offers US postal code database, search by state or city name.
http://www.daragon.com/zipcodes.html

ZIP Code Radius and Distance Lookup
Offers ZIP Code lookup, distance and radius search.
http://www.zipcodedownload.com/Lookup/

BrainyZip - Zipcode
Find out zipcode, State, County, Post Office Name, Latitude, and Longitude.
http://www.brainyzip.com

Postal Code Lookup
Search US and Canada postal codes by cities, towns and area codes.
http://www.postalcodelookup.ca/

MyZipCodeMap
Provides detailed map of all US zip codes, powered by google map.
http://www.myzipcodemap.com/

Zip Codes Finder
A zip code search offering city demographics, local weather and maps.
http://www.aresllc.com/zip-codes-finder/