US Zip Code - Offers US postal code database, search by state or city name. - http://www.daragon.com/zipcodes.html
Zip Codes Directory - Provides search for ZIP and area codes for a city. - http://www.1zipcodes.com
Find A Zip - A detailed database of all US Zip Codes, City Information and Area Codes. - http://www.findazip.com
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
USPS - ZIP Code Lookup - Look up a zip code by address, city and State. - http://zip4.usps.com/zip4/welcome.jsp
India - Postal Codes - Search for Postal Index Number PIN Code for the specified Locations. - http://www.mapsofindia.com/pincode/
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
France - Postal Codes - Offers zip codes search. - http://www.laposte.fr/sna/rubrique.php3?id_rubrique=59
Danmark Postal Codes - Find zip codes from street address and locations. - http://www.postdanmark.dk/contentfull.dk?lang=en
China Zip Codes and Area Codes - Offers Zip codes and area codes of major cities in China. - http://www.travelchinaguide.com/essential/area_zip/
Canada - Postal Code - Find Postal Code by street address, municipality and province. - http://www.canadapost.ca/tools/pcl/bin/advanced-e.asp
Belgium - Postal Codes - List of Postal Codes and its corresponding city. - http://www.charline.be/info/codepost/cpost.htm
Australia Postal Codes - Offers postal codes search by location and state. - http://www1.auspost.com.au/postcodes/
AskYP - Zip Codes - Find zip code by city and state and find city and state by zip codes. - http://www.askyp.com/Zipcode/
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
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/
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/
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
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
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/
DirectMailQuotes LLC - Zip code directory lookup as well as postal rates, regulations, glossary of mailing terms. - http://www.directmailquotes.com/postalregs/index.cfm
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
KJL Software, Inc. - Databases of US ZIP Code and Area Code information. - http://www.kjlsoftware.com/
PostalRates.info - Postal rates, post codes, philately and Postal Authorities around the world. - http://www.postalrates.info
Simply Zip Codes - ZIP code, city/state, area code lookup along with distance calculations and population data. - http://www.simplyzipcodes.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
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
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
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 - Current postage rates, Domestic, Europe, USA, cards and letters, in over 60 countries - http://www.atms.ch/rates