Harvard University
The Geoffrey Chaucer Page: Dante Alighieri Sketch
From Harvard's Chaucer Page, it focuses mainly upon how Alighieri influenced Chaucer, but you can view some texts of his here. This is a great site to check out on the subject.
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.