I haven't used Skype or Jing in my classroom but it would be a great thing to start using. Using either of the two can help you and your students communicate with anyone around the world for free. You can start using it as a way to get in touch with another teacher and her students as a pen pale method. Using Jing will help to share materials so that it can be used as a discussion on Skype.
I've included a video on how to use Skype in the classroom for beginners.