I read about this stuff a while back. You don't have to worry so much about the electromagnetic field. This stuff uses some crazy rules of quantum physics. Essentially the power gets transfered from one object to the other without traveling the space in between. I believe it's called tunneling.
It somehow locks on to the receptive unit and beams it power. It is freakin' awesome stuff. I wonder if they extended the range could they make lineless power poles?
Damn, do I ever love technology.