ReVIVE Solar ReStore XL 4000mAh Solar Charger Power Bank & USB Rechargeable External Battery Travel Pack w/ Universal USB Charging Port & High-Efficiency Solar Panel for MP3 Media Players, Smartphones , E-readers , iPad and More!
I love this solar charger so much!  It's perfect for festivals and camping.  It does take a very long time to charge via the sun but quickly when plugged in via USB.  I usually get 2-3 iPhone charges out of it.