I've owned a few solar chargers, from really small to the big Brunton 14 watt roll panel. So far, I have always come back to lithium batteries to power or recharge devices. They are light, can be placed in resupply packages and are rather powerful. I've bought gear to run on AA batteries wherever possible to be able to use them. The weight of the big useless Brunton panel with all the charger accessories needed to get the 12v output into batteries was a joke compared to what I now carry on a 3 week trip in Lithium batteries.
For small devices, look at the tiny Energizer Energi-To-Go chargers that are essentially a mini-USB cable to two lithium batteries - they work and are dirt cheap:
http://www.amazon.com/Energizer-Energi-To-Go-Battery-Operated-Instant/dp/B000IOKLZM
I got two of these for under $5 on Steep and Cheap last year - that's worth it for the lithium batteries included alone.
For extended trips away from the grid, or anything that needs more serious power and doesn't work with AA lithiums, I'd look into the Goal Zero Sherpa 50 coming later this summer: http://www.goalzero.com/sherpa50.html but we're talking 2 pounds here to charge a sat phone, a big camera or a small computer.
