ARTFL Project: ROGET'S Thesaurus Search Form
http://humanities.uchicago.edu/forms_unrest/ROGET.html
The ARTFL (American and French Research on the Treasury of the French Language) Project, located at the University of Chicago, have provided this online version of Roget's Thesaurus. The interface is simple--type in the word you want, and the form will return synonyms and antonyms. This site is among PC Magazine's Top 100 Web Sites.