I have had a lot of fun reading Jack Prelutsky's, If Not for the Cat with third graders.  It is a collection of haiku poems about animals.  The book is designed so you can read the haiku and students can guess what animal the poem is about.  Kids LOVE this.  Then we write and illustrate haiku poems.

A recent book that I have not yet shared with students is Kyoshi's Walk by Mark Karlins.  It is also about haikus.  A grandfather is walking and explaining to his grandson "where poems come from."