I've been learning to speak Thai for the last two years (casually, so I'm not anywhere near fluent!). I use Thai Style (http://www.learnthaistyle.com/) and have found it excellent. I do face to face lessons, but they do Skype (my teacher is moving back to Thailand at the end of the month, so I'll continue with this when she does). I have found it really reasonable from a cost perspective as well.