So, I'd like to let you know, that Skype could be very intaractive due to its"Extras". You can share not only your web-cam, or chat with, or call to each other, but also - your display(Oneeko - Extras), that could help you to share your PDF-books and other types of learning materials.
I would be glad to spend some time in helping you learning Russian, not only chatting about different things, but real brain-working
:)