Online Writing and Editing Resources

Oxford Dictionaries
Free and subscriber versions of the Oxford English Dictionary.

Dictionary.com
Free, online dictionary. They also offer a thesaurus.

Online Dictionary
Includes English language dictionaries, rhyming dictionaries, dictionaries specialized by field or profession and dictionaries in a variety of other languages.

Bartlett's Quotations
Free, searchable database of quotations.

Lexical FreeNet
Allows you to search for synonyms, rhymes, and quotations.