U.S. State Department travel advisories
http://travel.state.gov

British government travel advisories
www.fco.gov.uk

Canadian government travel advisories
http://www.voyage.gc.ca

U.S. Customs Service alerts (guidelines of items permitted and not permitted when traveling)
http://www.customs.ustreas.gov/xp/cgov/travel/

Passport Services and Information
http://travel.state.gov/passport/passport_1738.html

Foreign travel entry requirements
http://travel.state.gov/visa/americans/americans_1252.html

Tourism offices worldwide
http://www.towd.com or www.worldtourismdirectory.com

U.S. embassies around the world
http://travel.state.gov/visa/americans/americans_1252.html

Currency conversion
http://www.xe.net/currency

Create and print a currency conversion sheet to take along on your next trip
http://www.oanda.com/converter/travel

Metric conversion calculator
http://www.worldwidemetric.com/metcal.htm

Metric measurement calculator, including temperature conversions
http://www.admiralmetals.com/metric_conv.htm

World Clock
http://www.timeanddate.com/worldclock

Current time anywhere in the world
http://www.worldtimeserver.com

Info on airport facilities, terminals and parking
http://www.worldairportguide.com

Maps of locations worldwide
http://maps.google.com

International dialing codes
http://www.kropla.com/dialcode.htm

Weather forecasts worldwide
http://www.wunderground.com