In reference to the earth's magnetic field,
Magnetic fields cause the generation of electricity in certain metals but only when they are moving through the magnetic field (the principle behind motors and generators)
Maybe an enormous windmill with giant coils in the blades- the wind moves the blades, the blades move through the earth's magnetic field, and electricity would be generated? How big would it have to be to do anything useful?
Can magnetic fields be used in some other way to create energy? I don't know. The concept of many "perpetual motion" machines is that magnetic fields would make a machine run itself, which would then be used to run a generator or something. The problem is friction, heat, etc will leak energy out of the system until it grinds to a halt.
"I cool thing I did hear about magnets though was this guy from MIT developed a magnet device that will soon replace all cords and wires in that you place a main magnet"
Sounds like an induction charger:
http://en.wikipedia.org/wiki/Inductive_charging Nothing magical about this, one coil generating a magnetic field in the base, another one picking it up in the device and converting it back into electricity- the same way transformers work, and they've been around hundreds of years.