Wagan Tech inc has come out with a range of very conveniently sized (pocket-able) solar chargers for consumer electronics. They will charge batteries, iPods, digital cameras etc, all from the sun. The units themselves are very lightweight and come in two distinct types.

Blue Spark Technologies produce printed carbon-zinc batteries, which are small, environmentally friendly and most importantly cheap enough to produce to make them viable. These batteries are also incredibly thin; their standard battery is 750 microns thick (that’s 0.75 of a mm), while their Ultra-Thin series of batteries can go as slim as 500 microns.