» AT&T US Area Codes    List of US area codes for each state, with a list of important cities and towns in each of the telephone area codes. Provides good information on overlays and splits.    http://www.consumer.att.com/global/english/usa_codes.html

» Assist Book    Lists international dialing codes, area codes, weather, world time and currency exchange rates. Also has a reverse phone number lookup tool.    http://www.assistbook.com

» CE - US Area Code Changes    Lists of exchanges that have moved or are moving from one North American area code to another.    http://frodo.bruderhof.com/areacode/

» CountryCallingCodes.com    Online tool that builds dialing codes based on locations selected. Includes many international dialing codes and some area codes. Also has a reverse phone number lookup tool and current time.    http://www.countrycallingcodes.com

» CountryCodes.com    Online tool that build dialing codes based on locations selected. Lists many international dialing codes and some area codes.    http://www.countrycodes.com

» Dial Code    Find international dialing codes and area codes by specifying location. Information on direct dial prefixes. Flash user interface.    http://www.dial-code.com

» Dial Codes Plus    Listing of international dialing codes and area codes with instructions.    http://dialcodesplus.com/

» FAQs on Area Codes from FCC (USA)    The Federal Communications Commission answers frequently asked questions regarding area codes in the US.    http://www.fcc.gov/Bureaus/Common_Carrier/Factsheets/areacode.html

» Fone Finder    Enter the 3-digit prefix or the city name to find an area code.    http://www.fonefinder.net

» How to Call Abroad From US and Canada    Calling guide for United States and Canadian residents listing international country and city codes, phone books and time zones.    http://www.howtocallabroad.com/

» International Dialing Codes    International and national direct dialing prefixes and instructions.    http://kropla.com/dialcode.htm

» LincMad    Information about North American area codes, featuring changes, historical data and area code map. Detailed information on overlays and splits.    http://www.lincmad.com/

» NPA NXX Source    Databases for sale providing data on area codes and telephone exchange prefixes in the North American Numbering Plan.    http://www.npanxxsource.com

» North American Numbering Plan Administration: Area Codes    Find North American codes by a map, number, or location. Includes information on future planned area codes and a free downloadable area code database.    http://www.nanpa.com/area_codes/index.html

» TP2Location    Resolve any telephone number to its geographical location.    http://www.TP2Location.com

» Time Dial    Displays the current time, international dialing code, area codes and currency converter for almost anywhere. Includes instructions on country codes and international dialing code parts usage.    http://www.TimeDial.net

» Time and Date    International dialing codes for almost any country and area codes for many cities. The interface includes a dropdown selector and local times are provided with dialing codes.    http://www.timeanddate.com/worldclock/dialing.html

» UK Dial Me    A directory of telephone STD dialing codes in the UK.    http://www.dialme.co.uk

» UK Phone Information    Returns area information, map, BT charge information, and nearby exchange names for telephone numbers, access/short codes, or the name of a location.    http://www.ukphoneinfo.com/

» US Area Code Answers    Information about US-based area codes and prefixes. Find the city, carrier, location, and more information about any phone number with this free service.    http://www.areacodeanswers.com

» US Area Code Finder    Area code lookup for the United States with maps. Search by state or by code.    http://www.areacodesearchengine.com

» US Area Code Locations    Provides a list of towns and cities covered by each US area code including overlays and splits.    http://www.areacodelocations.info

» US Switchboard - Area Code    Find United States area code by city and state, Find City and State by area code.    http://www.infospace.com/swbd.main/white-pages/reverse-lookup

» Verizon - US Area Code Lookup    Find the major locations in a certain area code by entering the area code, or find the area codes that are used in a certain state by entering the state name.    http://www22.verizon.com/areacodes/

» World Search Dial Codes    Contains world telephone codes and time zone information. Search by city, country or number.    http://iptop.net/eng/code.html

» World Telephone Numbering Guide    Lists and links to current international dialing codes and area codes with formatting guides and provides information on recent and historical changes.    http://www.wtng.info/

» exUSSR Phone Codes    Includes all cities of Russia, Ukraine, Belorussia, Moldova, Lithuania, Latvia, Estonia, Kazakhstan, Georgia, Uzbekistan, Azerbaijan, Armenia, Kirgizia, and Tadjikistan.    http://phonecodes.narod.ru/