I don’t often write about gadgets that aren’t available yet, but I thought this particular product was worth a preview. It’s a charger for small devices like cell phones and iPods that you don’t have to plug in; in fact, it has no batteries at all. How does it generate power for your device? You generate it — by walking.

From a new company called nPower, it’s called the Personal Energy Generator, or PEG. The nine-ounce, nine-inch PEG takes the kinetic energy you create by walking or running and converts it into usable energy for your portable device (I was glad to see that nPower specifically lists the iPhone as a candidate for this power generation.)

Here’s the key part of the description, taken from the company’s Website:

“When a user carries an nPower PEG and connects it to a personal electronic device, the PEG provides a constant flow of electricity that charges the battery while the user walks. It allows the user to personally generate enough electricity to charge handheld electronic devices at the same rate as a wall outlet.”

So it’s not only useful, it’s also green — everybody wins!

A partial list of compatible gadget includes the aforementioned iPhone and iPod, Motorola cell phones, Magellan GPS units, Palm Treo, Nintendo DS Lite, BlackBerry and more. The company says that pre-order isn’t yet available for the PEG, but a consumer site listed the cost as $149. Since nPower did not list a suggested retail price yet, however, there’s no guarantee the PEG will come out at that price.