Management, and the layers of corporate bureaucracy that come with it, helped drive the growth of huge companies in the 20th century -- but it's looking increasingly outdated in the new millennium, writes Alan Murray. Business leaders need to learn to think less like managers and more like venture capitalists, Murray argues, in order to forge more innovative and responsive ways of running their companies. "Can the 20th-century corporation evolve into this new, 21st-century organization? ... The time has come to find out," he writes.