Website: http://www.classcraft.com/
Free iPad app: https://itunes.apple.com/us/app/classcraft/id968213964?mt=8&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/classcraft/id968213964?mt=8&at=10l6SU
Free Android Phone app: https://play.google.com/store/apps/details?id=com.classcraft.android
Free Android Tablet app: https://play.google.com/store/apps/details?id=com.classcraft.android
Free Android Phone app: https://play.google.com/store/apps/details?id=com.skype.raider&hl=en
Free iPad app: http://itunes.apple.com/us/app/skype-for-ipad/id442012681?mt=8&uo=4&at=10l6SU
Free iPhone app: http://itunes.apple.com/us/app/skype/id304878510?mt=8&uo=4&at=10l6SU
Free Mac program: http://www.skype.com/go/download
Free Windows program: http://www.skype.com/go/download
Website: http://skype.com/