Allen Holub has in interesting blog post on Dr. Dobb's in which he argues that agile organizations should ideally be organized as holacracies. A holacracy is an organization made up of autonomous units (called holons) that are independent but working towards the same goal.
Holub writes, "The notion of holacracy works well in agile organizations. In fact, I'd say that some level of holacratic structure is essential." He adds, "The holons carry out well-defined roles, and are responsible for doing whatever they have to do to succeed in those roles. Nobody orders anybody around. The teams and the people are responsible for defining and executing their own tasks."
He concludes, "I've said this before, but agile is a culture, not a set of practices. It is upper management's job to establish that culture, and then let it work. A holacratic organization is one of the better ways to do that."