I just use one of these or one of these . It will take a charge from the normal USB power limited 2.5W input (so will charge from a 4.5W Solar Panel or computer PC USB port). The charge will accumulate in the Lithium Battery and the outputs will have enough power (upto 10 Watts from the TecKNet iE380-II 7000mA Dual USB battery port) to charge all USB powered devices even up to iPad 2 etc. Its not as efficient to charge the main battery on the device you want to use but most device will allow operation when powered externally. It would take about 14hrs sun exposure using a 4-5W PV panel to fully recharge the iE380-II to give yourself a few hours iPad 2 use.

I wouldn't even bother attempting to hand crank charge anything as power hungry as a smart phone, even getting enough charge into a standard cellular handset to make a 1-2 minute phone call is a royal pain...