Yes I have been looking into the Alexander Technique myself recently. Originally I was hoping to learn from a book, but after having had one introductory lesson I now understand why it can only properly be learned from a teacher.
The teacher held my body in certain positions in order to limit their range of movement and asked me to move. By moving with these parts of my body fixed with relation to each other, I could then feel how the correct motion was meant to feel.
And actually it did feel great. I think it is hard to teach ourselves these new habits of motion, without a teacher showing us exactly what is the correct way of moving.
Anyway the main point I have discovered is that the Alexander Technique has a great many side 'benefits' for the practitioner. Included in this are boosted self esteem and a general increased sense of well being. Once we learn how to move with proper use of our bodies then we don't waste energy then we enjoy a heightened vitality and many other benefits including good posture.
I have not found Alexander Technique teachers to be prohibitively expensive, so I would encourage anybody else to seek out a teacher locally. Often introductory lessons last one hour and are reasonably priced.
One Alexander Technique resource which proved useful to me is here: http://www.atglasgow.com
I have not had another lesson, though I intent to. But i do feel I got a lot of benefit from the one initial lesson. It was a couple of months ago now. But still I feel myself practicing what I learned in that one session.