It's funny, because I have seen the windup cell phone charger appear in the gadget blogs again. I wrote a review of one of these devices, and you know what? The device doesn't work.

A UK gadget store sells the product and states that you must turn the crank vigorously for a few minutes and you'll get 25-30 minutes of talk time for your effort. Now you do get a charge while you turn, so it's not as if you get nothing. At least with my phones, I seriously doubt it's anywhere near that level of talk time.

Have you tried using one of these? Let me know your experiences!