A quick note: The Khan Academy, which already has a robust presence on YouTube and the web, now opens up shop on iTunesU. This gives students yet another way to access 1800+ video tutorials that teach the ins-and-outs of algebra, geometry, trigonometry, calculus, statistics, finance, physics, economics and more. The lectures, all taped and presented by Sal Khan, a Harvard MBA and former hedge fund manager, are watched some 70,000 times per day. And, with this new distribution channel, the numbers only promise to move higher. For more on The Khan Academy, see this August CNN piece. To download iTunes, click here.