Picked up one of these for my iPhone for camping. Solar charged speaker system. It gives up to 8 hours of playback on a single charge, and takes 5 hours to charge. Power is at a premium most places I camp as I am usually in unserviced sites, so this will be a huge help. I got it for $120 on Amazon, and the sound is very rich and impressive.
It is cool, and charges the phone too with the panel. I was skeptical it would be cheap and junky, but it is anything but. Awesome build quality, heavy, and as I mentioned, it sounds great.
It's mind bottling that phones don't all come with two front facing speakers already. Loving my Z3 for that reason (among others). Personally, I wouldn't want a bulky accessory like that to correct poor design in the first place.