GENERAL ENCYCLOPEDIAS

Encyclopedia Americana

St. James Encyclopedia of Popular Culture
in Gale Virtual Reference

Gale Encyclopedia of Multicultural America
in Gale Virtual Reference

ALMANACS

Infoplease
http://www.infoplease.com/index

ATLASES & MAPS

National Atlas of the United States of America
http://nationalatlas.gov/

TerraServer USA (topological maps & aerial photographs of the U.S.)
http://terraserver-usa.com

USGS Geographical Names Information System
http://geonames.usgs.gov/index

US Census Gazetteer
http://www.census.gov/cgi-bin/gazetteer

Xpeditions Atlas (National Geographic Society)
http://www.nationalgeographic.com/xpeditions/atlas/

Perry-Castañeda Library Map Collection
http://www.lib.utexas.edu/maps/

CALCULTORS & MEASURES

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

Currency Convertor
http://www.oanda.com/converter/classic

U.S. Weights and Measures
http://www.infoplease.com/ipa/A0001660

Metric Weights and Measures
http://www.infoplease.com/ipa/A0001659

DICTIONARIES

American Heritage Dictionary
http://www.bartleby.com/61

Dictionary.com
http://www.dictionary.com

Dictionary of Phrase and Fable
http://www.bartleby.com/81

Dictionary of Philosophical Terms and Names
http://www.philosophypages.com/dy/

Merriam Webster Online
http://merriamwebster.com

Roget's Thesaurus
http://www.thesaurus.com