The "Revolution" made by Sinewave Cycles is a neat bit of kit that we recently got the chance to test out, both here in the shop and on a Bilenky expedition touring bike that went on a trip to South America.
Sinewave Cycles (formerly BikeBright) is based in Cambridge, MA, and their products are made in the USA too. Here's why we like them so much.
The Revolution is simple and effective: plug it in to your front-wheel dynamo - in this case a Shimano DH-3D72; but it worked just fine with a Supernova Infinity too - and then use the USB outlet to charge up your iPhone, iPod, digital camera, or pretty much anything else with a USB port. (We even managed to charge an iPad with it, though we're not sure whether that's officially recommended!)
Although touring cyclists are not usually so concerned with the weight of their rig, for us one of the great advantages of the Revolution are it's size and weight. It really is about the same as a box of matches. It's sturdy and compact, easily tucked into a framebag. It's even water-proof (though thankfully we didn't have the need to test this claim)!
So we highly recommend the Revolution for touring. It doesn't have a battery for storage, but we simply unplugged the lights during the day and used it to charge electronics. It worked flawlessly. And there are other options too that you check out on the Sinewave website for charging or running multiple items.
The set-up was very simple. A Topeak RideCase iPhone holder mounts easily onto the stem without taking up handlebar space. Then just add your iPhone and the useful Gaia GPS app (maps can be downloaded) and hey - you're all set to explore...