Virtual Salt
Virtual Salt: A Glossary of Literary Terms
This site provides a long list of literary terms complete with full definitions and examples.
Other
Shakespeare Resource Center: A Quick Guide to Reading Shakespeare
A concise guide to how to understand Shakespearean English. Discusses word usage, grammar, wordplay, and versification.
Other
Bob's Byway: Glossary of Poetic Terms
Calling itself "unique," Bob's is easy to use, with cross-links throughout, phonetic pronunciation guides when necessary, and many examples and quotations. Click on the letter and scroll for the word.