The Constructive Teaching Centre in London carries on Walter Carrington's training for teachers of Alexander Technique, a continuation of F.M. Alexander's own teacher training.
AT and The Study of the Self
For extensive neuroscientific, philosophical, and educational context of Alexander Technique, visit the site for the Dimon Institute where AT is uniquely explored as a basis for The Study of the Self. Recommended: Ted Dimon's Anatomy of Directing.
Recommended Reading: Body, Breath and Being, by Carolyn Nicholls. Nicholls has done a terrific job describing the process of learning the Alexander Technique, step by step, with helpful pictures. The first chapter of Body, Breath and Being is particularly valuable, since it contains Nicholls' description of how to assume a powerful posture and practice called semi-supine, which you can do daily, on your own. There is no adequate substitute for in-person lessons, but this is a great introduction and companion to lessons with a trained Alexander Technique teacher.