My Favorite Screencasting Tool Now Works on Chromebooks
There is a free version and a paid “pro” version of Screencast-o-Matic. The free version will let you record for up to 15 minutes, record as many videos as you like, save to your Google Drive or local drive, and use your webcam while recording a screencast. The pro version removes the time limit, removes the Screencast-o-Matic watermark, enables cursor highlighting (that yellow circle you see on my screencast videos), enables drawing tools, and enables access to the offline editor.
more on screen capture and screencast in this IMS blog