If you find your phone dying while camping, you could always get the Solar iCharge at
www.solaricharge.com. This intro model acts as a case, a battery extender and a solar charger (very useful for emergencies). It's a great product as long as you realize that a full charge may day as many as 3-4 days of adequate sunlight to garner a full charge (this is the case with most chargers, we just try to be more honest about it).
The cool thing about Solar iCharge is that they offer a
trade-in program. So in the (very likely!) possibility that you get a new iPhone (or if Apple keeps changing those dang pin connectors on us ha), you're able to trade in your old charger and get a pretty decent credit towards another model. Score!