The best teaching ones I've seen are RotaryGolfSwing and Clay Ballard's Top Speed Golf.
Spent some time today and looked at both of them, looking that their 'free' introductory videos.
Top Speed Golf - found it much easier and simply to understand and find my way around the website. The free intro video's seemed to explain the concepts really clearly for me. Got something out of each to the point of considering signing up a for a month.
Rotary Golf Swing - just felt a bit too clumsy. From the website layout and info in the free intro video's to the way he tried to explain stuff. At twice the cost, I than Top Speed Golf, I doubt I would ever consider signing up.
I wouldn't use them at the exclusion of having an actual physical one on one golf lesson.
So, the question is - have you signed up to either?
Anyone else signed up?