Another great resource is Google Connected Classrooms.
Check out what this teacher has done using Twitter and Skype!
I love how he gets the students involved from the beginning!
Each time they run the exercise, students are assigned particular jobs: Among them, a “think tank” tracks maps, fact-checkers confirm what’s said, note-takers and runners make sure everyone has the information they need, and “on-camera talent” asks and answers questions. A student supervisor watches the whole process and looks for ways they can improve next time. A reporter-blogger documents the process.
For more on using Google Hangouts, click here