The main difference I can see between coaching and psychotherapy is that coaching is about positive changes that you can make in your life in order to maximize your abilities and potential, (which therapy and counseling also do), but coaching doesn't deal with pathology and isn't mental health treatment. Some counselors and psychologists also offer coaching.

As far as I have been able to tell, coaching doesn't seem to require licensure. There is training for it, but technically just about anyone could probaby hang out their shingle as a coach. Don't quote me on that though. I think the jury is still out and they probably are moving towards more certification.