Reference and Facts

Airports

http://www.fly.faa.gov/flyfaa/usmap.jsp

lists all major U.S. airports that are either experiencing delays or are affected by a traffic management initiative. 
 

Atlases

http://www.mapsarea.com/

http://www.lib.utexas.edu/maps/polar.html/

http://www.nationalgeographic.com/resources/ngo/maps/index.html

 

Calculators

http://www.martindalecenter.com/Calculators.html

http://www.wolinskyweb.net/measure.htm

http://www.megaconverter.com/Mega2/

 

Country Codes

http://www.usa.att.com/traveler/codes/index.jsp

Librarians Index to the Internet
http://lii.org/search/file/reference
Postage Rates
Wedding Anniversaries
http://www.chipublib.org/008subject/005genref/giswedding.html

 

Foreign Exchange Rates
FXCheatsheet: Travelers Currency Cheat Sheet
http://www.oanda.com/converter/travel
Universal Currency Converter
http://www.xe.com/
Updated daily. 62 major currencies plus gold, silver, palladium, and platinum prices. A "full" version is also available with 180 currencies for over 250 geographical locations, but without the gold, silver, and platinum prices. In addition, their Interactive Currency Table Converter allows you to create foreign exchange rate tables based on the currency of your choice, using current or historical rates. Also in French and Swedish.
Foreign Exchange Rates
http://www.federalreserve.gov/Releases/h10/update/

 

Weights and Measures
http://www.convertit.com/Go/ConvertIt/Measurement/Converter.ASP
Very easy-to use measurement conversion calculator. Use the 'Measurements Recognized' page to choose any combination of approximately 800 SI, metric, American, English, historical, and ancient measures.

Convert-me.Com
http://www.convert-me.com/en/
This site has interactive calculators for many common and exotic measurement systems, including metric, Ancient Greek, Roman, and old Russian. Measurements include weight and mass, distance and length, capacity and volume, area, speed, temperature, time, pressure, energy and work, circular measure, and computer storage. Also available in Russian (Cyrillic font).

 
How Many?: A Dictionary of Units of Measurements
http://www.unc.edu/~rowlett/units/
Includes all the units of the International System of Weights and Measures (SIPM); metric; non-metric scientific units such as the astronomical unit, the electron volt, and the parsec; the English Customary Weights and Measures; selected traditional units from cultures other than English; and other measurement terms and notations. Each unit's definition includes conversion factors.

 

Zip Codes

http://www.usps.com/zip4/