Words

The Visual Thesaurus
http://www.visualthesaurus.com/online/
Enter a word and get an interactive graphic "map" of its meanings, in a format like an animated word web.

Additional Sites Not in Book

The Rhyme Zone
http://www.rhymezone.com/
Enter a word to get rhymes, synonyms, definitions, and more for it.

The Cliche Finder
http://www.westegg.com/cliche/
Enter a word, get a list of cliches containing that word.

The Cliche Site
http://www.clichesite.com
Another cliche directory and search engine.

Dictionary.com
http://dictionary.reference.com/
An online dictionary and thesaurus.