Mobile Phone / PDA / iPod Charger
This is what we use ourselves when we're far away from the office - a solar power cellphone charger, complete with built-in storage battery.

The solar cells when folded have a footprint of just 137 x 79mm, making it a perfect, lightweight companion for any mobile phone. They charge virtually every mobile phone, PDA, and portable media player on the market, with the wide range of connectors and adaptors provided.

The storage cell is a high capacity Lithium-Ion battery. It can also be charged via DC.

Specifications:
Charger Output: DC / 4.5v ~ 9.0v @ 1.0A
Storage Cell Capacity: 2500mAh / 3.8v
Certification: CE and ROSH