How Wireless Electricity Transmission Works – Wireless Power Consortium
Slideshow explaining how the Qi wireless charging standard works…
Magnetic induction is a technology that you will probably remember from your physics classes at high school.
You need two coils, a transmitter coil and a receiver coil. An alternating current in the transmitter coil generates a magnetic field which induces a voltage in the receiver coil. This voltage can be used to power a mobile device or charge a battery.