How to use Arduino on Battery Power

Hi, just got the Arduino, very cool device. I'm using it for an art project that cannot be plugged in and needs to run on battery power. Would appreciate any advice on how to do this. I read a few posts but am a little confused as I thought the 5v and 9v labelled pins are for voltage out, not voltage in?

The 9V pin (and ground pins) can be used as voltage in too… you should be able to supply anything from 6 to 20 volts.

The 9V pin (and ground pins) can be used as voltage in too... you should be able to supply anything from 6 to 20 volts.

great, thanks for the info, I'll give it a shot

any chance of posting a pic of your set up?