Word Central:
Student dictionary and rhyming dictionary online at
Merriam-Webster's website. Daily Buzzword by subscription.
http://www.wordcentral.com/
Lexical FreeNet:
Allows you to search for rhymes and relationships between words and
concepts.
http://www.link.cs.cmu.edu/lexfn/
Semantic Rhyming Dictionary:
Rhyming dictionary and thesaurus: rhymes, near rhymes, homophones
synonyms, and semantic siblings of English words.
http://www.link.cs.cmu.edu/dougb/rhyme-doc.html
AnalogX - Rhyme:
[Windows] A rhyming program. Knows over 100,000 words. It can rhyme
words forward, backwards, and with matching syllable counts.
http://www.analogx.com/contents/download/audio/rhyme.htm
Rhymesaurus:
[Windows 95, 98, ME, NT and 2000] Free trial version available for
download. Rhyming dictionary and other lexical tools.
http://www.purpleroom.com/rhymesaurus/