No experience, but I have looked a bit into this before. Here's the first couple sites that came up under "buyers' guide online piano lessons" that might help think about what you are looking for:

http://www.makeuseof.com/tag/top-5-sites-for-learning-piano-online/

http://www.digitalpianoreviewguide.com/what-are-the-best-beginner-piano-lessons/