Udacity

From the Udacity website: We believe university-level education can be both high quality and low cost. Using the economics of the Internet, we've connected some of the greatest teachers to hundreds of thousands of students all over the world.

From the Udacity website: Udacity was founded by three roboticists who believed much of the educational value of their university classes could be offered online for very low cost. A few weeks later, over 160,000 students in more than 190 countries enrolled in our first class, "Introduction to Artificial Intelligence." The class was twice profiled by the New York Times and also by other news media. Now we're a growing team of educators and engineers, on a mission to change the future of education.

Publicly available: yes
Countries where available: Worldwide
Price range (USD): Free
Available online: yes