Words are Symbols Too

Alan Cooper's Homonym List
The best part about homonyms is that they are the raw material for puns, a truly sublime form of humor. With a robust knowledge of and appreciation for homonyms, you will never be embarrassed when a pun-battle breaks out in public.
www.cooper.com/alan/homonym_list.html

Allwords.com
Online Dictionary, Language Guide, Foreign Language and Etymology.
www.allwords.com/

AskOxford - the free online dictionary resource from OUP
Search the Compact Oxford English Dictionary online; get answers to questions on English, language, grammar, spelling, quotations, and usage; find out about OUP dictionaries; improve your writing skills; try word games, crosswords, and puzzles; win books in prize draw; learn French, German, Spanish, Russian, Greek, Japanese, and Italian.
www.askoxford.com/

Babble: The Wordgame Superchild of Scrabble and Boggle
Search the puzzle board for words of four letters or more. When you find a word, add it to your list using the form below the puzzle.
www.playbabble.com/

Fun-with-words.com - the Wordplay Web Site
Dedicated to amusing quirks, peculiarities, and oddities of the English language: wordplay. Playing with words and language is both entertaining and educational.
www.fun-with-words.com/

RhymeZone rhyming dictionary and thesaurus
A language arts reference tool and comprehensive search engine for words. Includes the functions of a rhyming dictionary, thesaurus, and spelling checker, as well as an integrated full-text search engine for all of Shakespeare's works and thousands of quotations and poems.
www.rhymezone.com/

World Wide Words
More than 1600 pages on the origins, history, evolution and idiosyncrasies of the English language worldwide. New words and words in the news are regularly featured.
www.worldwidewords.org/index.htm