Free Mac program: http://audacity.sourceforge.net/download/
Free Windows program: http://audacity.sourceforge.net/download/
Website: http://www.youtube.com/
Free iPad app: https://itunes.apple.com/us/app/youtube/id544007664?mt=8&uo=6&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/youtube/id544007664?mt=8&uo=6&at=10l6SU
Free Android Phone app: https://play.google.com/store/apps/details?id=com.google.android.youtube
Free Android Tablet app: https://play.google.com/store/apps/details?id=com.google.android.youtube
Google Chrome app: https://chrome.google.com/webstore/detail/youtube/blpcfgokakmgnkcojhhkbfbldkacnbeo
Website: http://www.nationalgeographic.com/
Website: http://www.khanacademy.org/
Free iPad app: https://itunes.apple.com/us/app/id469863705?mt=8&at=10l6SU
Free iPhone app: https://itunes.apple.com/us/app/id469863705?mt=8&at=10l6SU
Free Android Phone app: https://play.google.com/store/apps/details?id=org.khanacademy.android
Free Android Tablet app: https://play.google.com/store/apps/details?id=org.khanacademy.android
Edmodo app: https://spotlight.edmodo.com/product/khan-academy,324527/
Website: http://www.youtube.com/teachers