Thought I'd try this as a speaker for my PSP Go (or any portable device) as the speakers on the Go aren't the best and sometimes I couldn't be bothered with the earphones. Works quite nicely from the sample I tried.
Charging it the minute. Apparently the leaf on top will be green when fully charged and turns red when running out of juice. No on/off button, it's turned on when the audio jack is plugged into the speaker, even if audio device is turned off.