1054 CE: Great Schism: A description of the East-West Schism from National Geographic.
Great Schism of 1054. This website might look a bit junior, but the description of the Schism is very good, and the personalities involved are described. Also discusses the period of time after the Schism.
The Great Schism of 1054. This lesson in the history of the Schism is very detailed, giving a good description of the tensions that led up to it.