Ginsberg also has a book called "Spontaneous Mind"--it's a collection of interviews, that's pretty good stuff, too.
Also, Michigan University has a series--Poets on Poetry--get your hands on this series and just riff on what the people have to say. Some are more helpful than others. Yusef Komunyakaa's book is really good for poetics and theory, where as some of the Levine stuff is more about HIS poetry than poetics in general. But still worth reading.
Also, Mel Ash has two books out--Beat Spirit (I think it's called) and Shaving the Inside of your Skull. Both are good for artists in general.