Introduction to Psychology by Paul Bloom from Yale
20 excellent video lectures on some important concepts in psychology.
Introduction to Computer Science by David Malan from Harvard
Excellent video lectures that introduce the basic concepts of computer science.
Justice: What’s the Right Thing to Do by Michael Sandel from Harvard
Very interesting video lectures that discuss some of the moral dilemmas in the field of justice.
Entrepreneurial Thought Leaders from Stanford
Over 300 successful entrepreneurs and leaders including Mark Zuckerberg and Ev Williams discuss entrepreneurship in this seminar series from Stanford.
Psychology 156 by Dacher Keltner from UC Berkeley (iTunes)
This course on social psychology is excellent and Professor Keltner is a great lecturer. I highly recommend Lecture 29 which discusses the research on happiness.
Computer Science 61B by Professor Jonathan Shewchuk from UC Berkeley (YouTube)
Professor Shewchuk does an excellent job at explaining important concepts in computer science including how Java works in this series of video lectures on YouTube.
Talks at Google (YouTube)
There are a ton of great talks here from various interesting people including authors, leaders, and change agents (Google should create their own free college!).
Additional Lecture Sites
Lynda.com
While these are not college lectures and not free, Lynda.com offers tons of great technology courses for $25 per month including courses on CSS, programming, Photoshop, time management, and many more.
The Great Courses
Another premium site which offers a lot of great college lectures at various prices.