Wireless technologies improve every year, and today you can easily build a home network with dozens of piece of wireless equipment that help reduce clutter and give you more freedom when using your hardware. One of the biggest setbacks to wireless devices is the fact that they must be powered, and as such today rely critically on batteries. Whether it be a rechargeable built-in battery or ones that must be changed, these devices must be able to process input and receive/transmit data. To that end, Powercast has been working on "power over wireless", in which they will be able to modulate RF enough to carry data yet still maintain a constant voltage, enough to power a device.

It isn't a completely elegant solution, requiring a secondary transmitter that will supply power when within range:

The system basically consists of two parts – a wall-plug transmitter and a "dime-sized receiver" that handles the real magic – and energy is instantly transmitted whenever that disc comes within a yard or so of its tag-team partner.
While this isn't the only solution out there, it has a lot of funding and some big names behind it, such as Philips. Back in January, Powercast talked about their creation. The potential for this is quite wide, and it would be fantastic to have wireless controllers, keyboards and mice that never need to be recharged. The units apparently are very cheap to produce, and the technology could be integrated in the future directly into devices. Interesting stuff.