Company to Offer Motion-Based Phone Charger

Exercise issues aside, having something like this available would cut down on unnecessary use of energy. There've been many articles talking about how much wasted electricity that the wallwarts use. Wouldn't this be a nice subtle way for the cell companies to go green?
I've had a selfwinding watch for a number of years and its done well for me. I was just thinking about something like this the other day built into dress shoes, but having a device like a reverse pedometer that generates electricity would be great.