How much money could you make from a technology that replaces electrical wires? A startup called Powercast, along with the more than 100 companies that have inked agreements with it, is about to start finding out. Powercast and its first major partner, electronics giant Philips, are set to launch their first device powered by electricity broadcast through the air.

It may sound futuristic, but Powercast’s platform uses nothing more complex than a radio–and is cheap enough for just about any company to incorporate into a product. A transmitter plugs into the wall, and a dime-size receiver (the real innovation, costing about $5 to make) can be embedded into any low-voltage device. The receiver turns radio waves into DC electricity, recharging the device’s battery at a distance of up to 3 feet.

Picture your cell phone charging up the second you sit down at your desk, and you start to get a sense of the opportunity. How big can it get? “The sky’s the limit,” says John Shearer, Powercast’s founder and CEO. He estimates shipping “many millions of units” by the end of 2008.