A New York Times article discusses a move by Chicago to shut down 60 underperforming schools and replace them with 100 new schools, more than half of which would be run privately and outside of the current teacher's union contract.
The move, called Renaissance 2010 is intended to replace larger, failing schools (ones that would be brought under federal management under the No Child Left Behind laws) with smaller neighborhood schools. As a part of this, more charter schools will be created and a number of the new schools (approaching 60 of the 100) would be under private control and outside the control of the powerful Chicago Teachers Union.
It's not the first time that this kind of thing has been tried, but it is likely the largest scale project undertaken and certainly one of the few that undermines the teachers union.
The concentration will be on decreasing the size of high schools in order to fight what has been a problem of under-performance at the upper grade levels.