Term Explanation: 

Tai-Chi, in Chinese, means "Supreme Extreme". As the philosophy of Taoism, it means a certain state of the any object, which can be a person or even the universe. (Yes, human and the nature are connected in Taoism). As the philosophy says, Tai-Chi comes from Wu-Chi ('Empty Extreme"). Both the concept of Tai-Chi and Wu-Chi is between being and not being. From Tai-Chi, Yin and Yang are evolved. Yin and Yang means the opposite properties inside any beings.
 
 

What is Tai-Chi?
The history of Tai-Chi
A man within direct lineage of Wu School Tai-Chi in UCLA
 

 
Here is another web site where I find there are a lot of  information about Taichi, or even other things related, if you have time, you can go and see. Although it is mainly about Yang School Tai-Chi, Wu school and Yang School are directly related. I even think this is the best I have ever seen from WWW about TaiChi.
It also has some contents about Wu School Tai-chi, you can take it as a reference.