Yes, you can use Skype. (Skype.com) Skype is free, and even better, the teacher can "screenshare" with you. In this way, you can talk about pictures, graphs, articles, and even use MS Paint like a whiteboard.
If you want, you can do a demo class with me, and I can show you the tricks about teaching with Skype.
I hope to hear from you soon - EnglishWithDave