This is a collection of sites that provide dictionaries, thesauri (moose; meese:: thesaurus; thesauri), translation engines and linguistic and etymological information.

English Dictionary/Etymology 

http://www.askoxford.com

This is the free, on-line version of the Compact Oxford English Dictionary.

Dictionary/Thesaurus 

http://www.wordsmyth.net

This is a good on-line dictionary with a thesaurus function.

American English Dictionary 

http://www.bartleby.com

Ahhh, Bartleby.  These good folks are nice enough to provide us with searchable versions of both Roget's Thesaurus and The American Heritage College Dictionary.

Modern Language Association 

http://www.mla.org/census_main

The Modern Language Association has compiled this series of maps of the linguistic make-up of the United States based on the 2000 U.S. Census.

Translation 

http://babelfish.altavista.com

Babelfish is a good site for translating words, sentances or web sites either to or from English to a number of other widely spoken Languages.