Spencer Michels at the website of the PBS Newshour:
A 33-year-old math and science whiz kid — working out of his house in California's Silicon Valley — may be revolutionizing how people all over the world will learn math. He is Salman Khan, and until a few months ago he made his living as a hedge fund analyst. But he's become a kind of an unseen rock star in the online instruction field, posting 1200 lessons in math and science on YouTube, none of them lasting more than about 10 minutes. He quit his job at the hedge fund to devote full time to his Khan Academy teaching efforts, which he does essentially for free…
Khan's story — featured Monday on the NewsHour — is inspiring. A math and science graduate of MIT with an MBA from Harvard, he was one of those math-savvy kids who did great in school, and then decided to make some money. As an Indian-American (born in New Orleans), education — especially math and science — were important in his household. But when one of his cousins, a seventh grader, told him at a family gathering that she was having trouble with math — especially converting grams to kilograms — he decided to help her, long distance. He devised a method where he talked to her via the computer, with a blackboard on the screen, and after a few weeks she started to get it. Her progress was speedy, and he decided that the method he'd improvised, would work for others.
So he began putting short math lessons on the Internet, never showing his face, but keeping it simple and direct. He has a great gift for communicating, for explaining math concepts that I used to have problems with, and so did a lot of others.
More here. And here's a short overview video about the Khan Academy [recipient of the 2009 Microsoft Tech Award in Education]: