I was just using my phone as a camera last year and it was dying every day so I used a mix of car charger and the handy dandy Verizon charging tent.
Verizon also has a bunch of cell phones that you can use if (like mine) your phone doesn't work at the Gorge or in the states at all.
Also if your phone does work you can text it from those phones and then send all sorts of things in return for the next poor schmuck who uses it. A fact that my bro in law took advantage of a leetle too much.
It works great - I can charge my iphone 2x off it or my ipod 3x off it. Mine came with a suction cup, you stick it in your car windshield or whatever before you go in for the day, charge your phone at night.
Mine came with a USB adapter as well as a bunch of others for blackberries, nokia phones, etc. You can buy additional adapters for whatever phone / device you need to charge.
They have other products too, I assume they all work more or less the same.