Forget PowerMats and wireless charging and the like, because the Airnergy wi-fi signal harvester is my new front runner for the future of gadget charging.

It's not exactly new tech, as ohGizmo notes, but it's the first application that's of any real use to consumers. Put simply, Airnergy takes the energy created by wi-fi signals and stores it in a rechargeable battery. At CES, the device's battery, which I believe was precharged with Wi-Fi power, was able to charge a BlackBerry from 30% power to full power in about 90 minutes.

Pretty handy, and supposedly available this summer for $40. Not too shabby, and very appealing considering how ubiquitous wi-fi hotspots are these days. Very simple, somewhat cheap and incredibly useful if it works are advertised—by far one of the coolest things I've seen come out of CES this year. [OhGizmo]