Always a great list of current submission calls on NewPages!
NewPages is known as being a great resource for creative writing resources in general. Not only do they include listings for workshops, conferences, and writing contests, but they include a Calls for Submissions list which is kept updated with current open calls. You can also search by genre and type, i.e. Poetry/Chapbook.
Just make sure to read the submission guidelines carefully. For most editors, not following the guidelines is an instant rejection.