I've always learned on-the-job, in real time. A problem comes up; I research it, and try to solve it. You can't study to be an entrepreneur; you have to develop those skills day in day out. All entrepreneurial experiences are related, whether you're selling worm poop to Wal-Mart or a grade tracking application to the public elementary school system. In the end, it's all very similar.
Revolution in a Bottle: How TerraCycle Is Redefining Green Business (ed. Penguin, 2009) - ISBN: 9781101022214