Just come across this new solar charger from the US called the Solar JOOS Orange. It claims to be far more efficient than anything else on the market, able to give you 2 hours of talk time on your mobile after only 1 hour of charging in the sun (see their chart).

It's rugged and waterproof and so ideal for bringing your dead phone or DS back to life while camping.

Well it looks like a solidly made charger and if their claims are right it'll be a big improvement. It's quite expensive $100 (no UK price or availability as far as I can see). You get connectors of Micro USB, mini USB, standard female USB and connectors for LG, Samsung, Nokia included but it looks like you have to buy the connectors for other devices (around $5 each).

Well I don't have one to test, but Wired gave one a once over and were very impressed.

The Joos Orange solar charger is the physical manifestation of simplicity. It's rugged, easy to store and carry, and (most importantly) quick to bestow a watt or two whenever you need it. Simply choose the correct adapter (the Orange comes with seven of the most popular ones), plug in your depleted phone or DS into the charger and let the life-giving juice flow. Yep, that's it.