PowerFilm USB + AA Solar Panel Charger
I think I'll share my experience with this product. This is basically the review I wrote for Amazon:
I used it during a 10-day bike tour to keep my iPhone 3GS charged. In strong sunlight it'd charge the iPhone from low 40s% to nearly full in about 3-4 hours. It will even charge, although slowly, in overcast conditions. It's not powerful enough to run the iPhone AND charge it at the same time, but that wasn't my intention. I just wanted to make sure the phone is charged up at the end of the day so I can do some emails, listen to some music and play some games at the camp. To speed up charging I would put the iPhone in the airplane mode. I was out of range most of the time anyway so there was no point keeping it on. I pre-charged the batteries at home before leaving using regular charger. Note, that it will not charge your USB devices if the batteries are not present and at least partially charged!
They also make more powerful panels that will run AND charge an iPhone at the same and do it faster. I will have a look at those for the next time. However, this one is the right size to attach it to a pannier or backpack. It even has convenient, reinforced holes in all corners. I used bongo ties to attach it to my pannier.
I am very happy with this little charger. But it spoiled me, so now I want a more powerful one :D
Amazon product link
PowerFilm home page
It's very flexible and very light. It has a USB port so you can plug in your iPod or iPhone using the regular cable, no extra cables or adapters are needed.