RhymeBrain – Rhyme Any Word
http://rhymebrain.com/

Using advanced artificial intelligence techniques, RhymeBrain figures out how to pronounce a word even if it has never seen it before. RhymeBrain then compares it to the 260,000 words in its database to find ones that sound similar. Finally, it sorts them so that the best rhymes appear first, using their RhymeRankTM system. This has been added to the tools section of Research Resources Subject Tracer™ Information Blog.