Zen and Leaves: Japanese Tea Ceremony is a brief introduction to the history and significance of the tea ceremony.

Chaji is a detailed description of the tea ceremony where a meal is served.

The Japanese Tea Ceremony from Wikipedia is a well organized article with information about the history and implements of the tea ceremony, plus connections to art and interesting illustrations..

Essencha is a local (Cincinnati) "contemporary tea cafe and tea store whose goal is to provide the very best the tea world has to offer." They sell many varieties of tea, from black to green to herbal. The site gives basic information about each tea.