There is water sloshing around in the see-through heel of these shoes; all that water movement drives a tiny turbine. When in motion, the current prototype shoe can generate 1.2 watts of electricity, which is enough to power your iPod. You got to like that - enforced exercise, just to listen to your favourite music.
The developers, Telecoms giant NTT, hope to have the power generation up to 3 watts of electricity by the time these shoes go into production in 2010. That would generate enough power for your cell phone. It all sounds wonderful as nobody likes a dying cell phone battery, but where does the wire go? Up one's pants?