Consequence of change in learning - teachers have to give up power

Listening to Howard Rheingold at the questions session on #change11 MOOC brought home to me how reliant we are as teachers on control. Control of the learning environment, control of what is taught, control of what is assessed, control of the learner. Some of this is inevitable. But if we are to go towards open processes, then some of it we have to replace.
Rheingold had three relevant statements on the subject:
He tells his students that "absorbing all is not the goal but making sense of it together is" and that it is "scary and difficult for a teacher to give up power to the student. It is very rewarding once you do it, but you give them the responsibility to learn." Also, students "students cannot come into the classroom to be passive".
Of course, age is a factor. I agree with this approach 100% for university level students. We in schools should be weening our students towards these approaches. When? Well, I do think we have some of this in many Primary schools just by the nature of how they operate. In ours, we use the International Primary Curriculum and so the approach hands over some curriculum and learning control (although teachers work really hard in planning for such a programme).
It has caused us to re-think our 6th - 8th grade programme and to plan for more "open" approaches. To do this, teachers have to give up some power. How much? With what and where?