So we've been playing with the Devotec Industries Solar Sound
Bluetooth speaker system for a couple days now, and we've got to say we're pretty impressed -- we just wish it could run directly (and indefinitely) off the solar panel, instead of requiring an internal battery that takes 12-24 hours to charge from the sun or four hours to charge off USB. That said, you will get eight hours of decent audio when the battery is full, and it's actually relatively loud -- you'll be more than fine indoors and in quieter spots, although cranking things up all the way results in some audible distortion. Of course, it's A2DP, so setup is a breeze with most Bluetooth devices, including 3.0 iPhones, and you can hook most everything else up with the included 3.5mm headphone cable. (Just keep in mind that Apple doesn't properly support AVRCP, so the forward and back control buttons don't work correctly over Bluetooth.) Not bad for $79 -- and you won't have to burn through endless AAs to take your tunes on those summer picnics and beach trips.