I could say more good things about the Institute of Children's Lit - they give you two years to complete the program (if I remember correctly - lol) and have regular assignments. If you need more time for any one assignment, you just have to let your instructor know. You get VERY detailed feedback from your instructor. I worked one on one with mine and she was extremely helpful. The assignments were varied. Some were fiction writing, some non-fiction, some were about finding publishers, some organizing and getting ready for a novel. Even though it was geared towards writing for children, it still had a lot of info that could be applied across the board for any type of writing.
That is the only course I know anything about, but I would love to find out more about others, so I'll be following this thread to see if anyone else adds anything.