Website: http://www.classdojo.com/
Free iPad app: http://itunes.apple.com/us/app/classdojo/id552602056?ls=1&mt=8&uo=4&at=10l6SU
Free iPhone app: http://itunes.apple.com/us/app/classdojo/id552602056?ls=1&mt=8&uo=4&at=10l6SU
Free Android Phone app: https://play.google.com/store/apps/details?id=com.classdojo.android
Google Chrome app: https://chrome.google.com/webstore/detail/pbinoojbbajacmkigmfnkclhgjnglpon