Khan Academy

http://www.khanacademy.org/#browse

http://en.wikipedia.org/wiki/Khan_Academy

Salman Khan is a Bangladeshi American born and raised in New Orleans, Louisiana. His father is from Barisal, Bangladesh and his mother was born in Kolkata, India. Khan holds three degrees from the Massachusetts Institute of Technology: a BS in mathematics, a BS in electrical engineering and computer science, and an MS in electrical engineering and computer science. He also holds an MBA from Harvard Business School. In late 2004, Khan began tutoring his cousin Nadia in mathematics using Yahoo!'s Doodle notepad. When other relatives and friends sought his tutorial, he decided it would be more practical to distribute the tutorials on YouTube. Their popularity there and the testimonials of appreciative students prompted Khan to quit his job in finance in 2009 and focus on the Academy full-time. Bill Gates once said that "I'd say we've moved about 160 IQ points from the hedge fund category to the teaching-many-people-in-a-leveraged-way category. It was a good day his wife let him quit his job."

As of December 2009, Khan's YouTube-hosted tutorials receive a total of more than 35,000 views per day. Each video runs for approximately ten minutes. Drawings are made with SmoothDraw, which are recorded and produced using video capture from Camtasia Studio. Khan eschewed a format that would involve a person standing by a whiteboard, desiring instead to present the content in a way akin to sitting next to someone and working out a problem on a sheet of paper: "If you're watching a guy do a problem [while] thinking out loud, I think people find that more valuable and not as daunting."

I could have sworn I had already posted about Khan Academy, but as I've been using it more and more I wanted to do a more thorough recommendation.  A quick search shows I haven't posted about it yet though.

Either way, it is a great website that covers math and science from a beginning level up to undergrad.  His videos are quite good, better than most standard videos out there of this nature.  I won't spend a lot of time describing the style, just watch some of them.  Even if you are already learning this stuff in a real school, it is always nice to have a second explanation for new concepts.  In addition, it's nice to be able to just jump to subjects that may interest you.

There are about 2,000 videos of about 10 mins each, which works out to about 330 hours.  There are also about a 100 sets of 75 problems each for you to work out.  If you log in it keeps track of what you've done and watched.