I received an email from Dr. Tobias Lorenz telling me about Glovico, a Fairtrade online school where native speakers can teach their mother tongues via Skype: "... we want promote additional income opportunities in the developing world and foster intercultural dialogue. Having started out with Spanish and French last year we are currently moving into more regional languages at the moment."
This feature from BBC will give you a better idea of the venture.
If you're a learner, the first lesson is free and there's a money-back guarantee, so you can't go wrong really. If you're a teacher, you're not going to become rich—the recommended asking price for a 55min lesson is €5 to begin, so perhaps that's why there are only two teachers offering English lessons at the moment. However, if you're not in it for the money and want to get some experience of online teaching, Glovico could be the answer.