Taijiquan (t'ai chi ch'uan, tai chi chuan--all pronounced "tie-gee-chwan") classes are available at many venues around the world. Check your local telephone and web listings, or with alternative health practitioners or natural foods stores in your area.
Classes in Minneapolis, Minnesota with Barbara Davis, editor of Taijiquan Journal, can be found found here.
Taijiquan class information for United States and Canadian north-central states and provinces (Minnesota, Wisconsin, Iowa, South Dakota, North Dakota, Manitoba, and Western Ontario, can be found here.
An international listing of thousands of different taiji school websites can be found at Tai Chi Links. Remember though, many highly qualified teachers do not necessarily have websites.