[ http://www.collinslanguage.com/ ]
Buy downloadable dictionary software and online subscriptions to the best language resources.
[ http://www.lexfn.com/ ]
Rhyming directory. Lets you enter a word and other words that rhyme will be displayed. Offers suggestions too.
[ http://www.macmillandictionary.com/ ]
An internationally recognised publisher of encyclopedias, dictionaries and reference works.
[ http://www.wordcentral.com/ ]
Student created dictionary that also has a rhyming section. Daily buzzword available if you subscribe.