I write about T’ai Chi as a meditation because the slow, gentle “forms” are like a moving meditation. You gain physical strength and balance through the series of concise rhythmic movements, while at the same time you are focussing your full attention (mindful meditation) on each individual movement.
With the careful concentration and slow actions involved in this martial art you are not likely to end up with injuries. My aunt started going to tai chi classes when she was about 85! Now, don’t let that fool you into thinking that it is going to be too easy, because much like yoga, the more you practice and learn, the more challenging it can be. There are many dvds available for learning tai chi at home. This one T’ai Chi Beginning Practice – has clear verbal and visual instructions. I would suggest attending classes in person if you can. Taking classes can be extremely beneficial because a teacher can often spot incorrect movements and help you correct them before they become a habit.
I’ve only attended a couple of drop in sessions of Tai Chi so I had to enlist the help of Google to find good information for you. This article called Essential Tai Chi Principles by Dr Paul Lam and Nancy Kaye outlines the basic principals that anyone considering learning Tai Chi should know. The same website has a whole series of useful articles about Tai Chi.