UniversityNow: A venture-backed startup focused on taking student debt out of the education equation. Check out their TED Talk to learn more.

CourseRA: “Coursera is an education company that partners with the top universities and organizations in the world to offer courses online for anyone to take, for free.”

Cosmo Learning: “We believe anyone in the world is entitled to a free education of the highest quality. With the increasing availability of thousands of free video lectures by the world’s top scholars and independent contributors, we chose to devote our time and energy to share as much free educational content available on the Web as possible, bringing to our users a friendly and intuitive environment for learning.”

EdX: Integrates online course videos and peer-to-peer social networking experience. Watch their video for more information.

Udacity is “reinventing education for the 21st century by bridging the gap between real-world skills, relevant education, and employment. Our students will be fluent in new technology, modern mathematics, science, and critical thinking. They will marry skills with creativity and humanity to learn, think, and do. Udacians are curious and engaged world citizens.”

MIT Online Classes: “The idea is simple: to publish all of our course materials online and make them widely available to everyone.”
Dick K.P. Yue, Professor, MIT School of Engineering.
They are well on their way, with materials from 2,150 courses online.