Just had another thought - I've just got a brilliant little Blackburn front light which charges using USB - I bet my little PowerMonkey would charge that too.

By the way - I did have one of those Solio solar chargers & to be honest I didn't find it that great. One of the problems (aside from charging) was that it didn't come w/ many/any tips & they were really expensive. The PowerMonkey nuts are really cheap.