How to charge my iphone without wall outlet?

I'm planning on a long-distance walk across Europe, and I was hoping to find something to charge my Iphone along the way. Since outlets will be rarely available, I'm hoping to find a charger than converts power from, say, a AA battery to the Iphone. Does anybody know of something like this?

Solar charger

I'm sure you could adapt a hat so you wear it atop your head and charge during the day while youre walking.

There's an IPhone case on Amazon.com that acts as a charger. You charge the case and it will charge your iPhone when needed.

Certainly, there are dozens if not hundreds of products that will recharge a cell phone from a AA battery or batteries. Here is one http://www.bestbatt.com/Portable-Universal-Cell-Phone-Charger-p/bbemchg.htm?Click=247697&vfsku=BBEMCHG&gpla=pla

I think using AA's is a good plan, because they're standard worldwide, and can also be used to power other things such as a camera and LED flashlight. If you standardize on AA's, you can bring extras, and charge them from an outlet when you have one available. And in an emergency, you can take the last working batteries from one device and move them to the device that you really need. Get a charger that works from 100 - 250 volts AC. Most of the chargers you buy today have that rating.

I don't like the idea of a solar charger in situations like these, because it could be more trouble than it's worth. It takes hours for a solar charger to work, and you'll constantly be worrying about pointing it at the sun.