Solar Chargers for Phone - Did anyone try with Nokia 5800 XpressMusic?

Solar chargers are being very popular among mobile users as an alternative to regular chargers. In United States, most of the people use such chargers to charge their iPhones. Solar chargers employs solar energy to supply electricity to devices or charge batteries and generally portable in design.

Did anyone try these mobile phone solar chargers for their Nokia 5800 XpressMusic? I am interested to know how much they are capable of charging and is it really worth purchasing them. Some of the name I am aware of are: Power Monkey, Sunttrica, Solio and freeloader. Guys, post your comments and suggestions.