I've been doing Coursera for a few months now. Recently finished Model Thinking and Probability Graphical Models, and sort of relearning Automata Theory (I'd highly recommend Model Thinking, though).

I've been looking at MIT OpenCourseware too. They're not full classes like Coursera...they only offer lecture slides and assignments. I was looking at their Machine Learning course today.

Stanford has a few online course initiatives (Coursera is one of them). They seem to be more like coursera.