David Belew asked that I compile a list of Summer programs in creative writing. These are of two sorts: colonies/conferences and academic programs.
Based on reports of the writing colony experience I have not had, I would recommend programs unless or until winning a fellowship, scholarship, or otherwise subsidized stay at a colony, such as Breadloaf, where hierarchies of paying vs. non-paying writers often develop.
The Poetry Society of America keeps an excellent list of links:
Iowa Summer Writing Festival
Summer Literary Seminars in St. Petersburg, Russia, and in Kenya (don't know if Kenya is the place to be this summer -- though maybe it is? --)
New School for Social Research:
Then there are also continuing education courses in creative writing, such as those at New School for Social Research, Naropa, Columbia University, UCLA Extension. These are year round (not summer only) and occasionally online or for graduate or undergraduate credit:
Boston University has a summer term with creative writing courses.
So does Harvard, however many of these are not workshops led by published writers: google the faculty.
The Kenyon Review has one at Kenyon in Ohio:
Antioch's in Ohio is only a week:
(there are lots of them which are just week-long intensives with lots of exercises, for example Wesleyan (CT), Aspen (CO), etc.)