I finally made the effort to teach online! My nephew needed some help with his GCSE mathematics, but he is in London and I am in Georgia! So, using Skype and a paper flipchart stuck up on my living room wall, I proceeded to help him and a friend with their calculus questions. They loved it, and in fact, other students (he is at a boarding school) gathered around while we were working.
I then went searching for a wonderful tool I used a few weeks ago - WizIQ. I't allows you to teach live online using your webcam and a virtual whiteboard. I tried it and it seems quite easy and useful. I'll post some more details later, but in the meantime, check it out at
http://www.wiziq.com