The absolute best way, bar none, to learn Tai-Chi is personal
instruction. This, incidentally, holds true for any Martial Art, but with
Tai-Chi's complexity (when to inhale, how to angle your foot, the proper speed
to turn around, etc) it is especially true.
Checking your local listings for an instructor or school is a good
start, as is asking anyone you know who is involved in Martial Arts. Ta-Chi is
a Chinese Martial Art; it is Kung Fu. If you find a school offering Tai-Chi
along with a host of other styles, many of which are not Chinese styles, be
wary. The style's popularity makes it a
profitable addition to a school's offerings, but does not guarantee the school
knows it's stuff. Ask how long they have been teaching it, where they learned
it from, etc.
Can you learn Tai-Chi from
a book?
Yes, provided you are already a Martial Artist and you follow up
your self-training with person instruction. A book can be a fantastic resource,
especially if it includes lessons on Qigong and is well illustrated with clear
images. However, a book can't notice if you've mis-learned something. Repeating
a wrong move a thousand times makes it much more difficult to unlearn than if
an instructor caught you the first time.
What about videos?
There are some quality Tai-Chi videos, especially on DVD; however
there are just as many that are dreck. Many "Tai-Chi for Fitness"
types give a brush-over lesson on breathing (if that) and go right to the
postures. Many of those do not ever touch on combat applications. Even if your
only goal for learning Tai-Chi is for health its benefits, you still need the
proper Qigong training in order to get them.