I have taken any of their online courses, but I have taken a lot of regular courses at the International School of Photography in New York. Generally, the quality of instruction (and the quality of your fellow students) is very high, with lots of creative work to inspire you.
Their online courses are synchronous (i.e., all the students need to be logged in at the same time). There are just a few courses listed right now (with classes starting later this summer), but generally they have 6-10 courses starting each term, with the next major term starting at the beginning of October. You can get a sense of the kinds of classes they offer online by looking at the PDF of their summer catalogue, where you can see the range of courses they offered in the summer term online.
Online Education | International Center of Photography
I have taken online (asynchronous) courses with Bryan Peterson School of Photography (bpsop.com). Quality varies (some have been superb, others so-so). They are geared more towards novice-intermediate students.
Some of the courses focus more on creative approaches. Check out Joe Baraban's photography - if you like his photos, you might like his classes. (I signed up for one and hated it, but that's just me.)