Martha, a reader from Idaho, recently sent me an email : "Please let people know that there's a wonderful site, Kalliope, that really taught me how to write poetry and understand the different forms of poetry."
An introduction from the site: "Each session, we post a Primer, discussing one aspect of poetic theory or technique in detail, with examples. Each Primer includes one or more Exercises designed to practice the techniques discussed in the Primer. The Primers are archived on our web page. Later Primers will be available only to members, but the beginning Primers are available to all.
The only requirement for membership in Kalliope is a willingness to work at your craft and to help and encourage your fellow poets. We all need feedback, and we learn by critiquing as much as we do by writing.
We also encourage studying all sources on the craft of the Muse, and above all -- reading good poetry. We have compiled resource pages, including both lists of good and useful books in print, and links to great poetry resources on the Web.
The exercises in the Kalliope On-Line Poetry Workshop have been designed to cover a wide spread of the aspects of poetry, from the most basic to the most advanced. We are adding to them on an ongoing basis, and we welcome suggestions."
If you don't want to join—take a look at the archived exercises.
They're quite interesting and one can pick and choose or follow her order.