The beliefs of Anglicans can be quite diverse. The official standard is some version or derivative of the Book of Common Prayer but some parts of that book are more clearly doctrinal than others. The Catechism found in most editions of the Book of Common Prayer summarizes the faith in question-and-answer format.

The ecumenical creeds, both Nicene and Apostles, are used by the Anglican Communion in its worship day by day and week by week. They are ancient and universal statements of Christian faith. In addition, many Anglican churches follow ancient tradition and include the Athanasian Creed among their statements of faith.

Another very important ancient statement of faith is the Chalcedonian formula, which defined the limits of Christological orthodoxy.

The Chicago-Lambeth Quadrilateral describes the general ecumenical principles of Anglicans.

The Thirty-Nine Articles were important at the Reformation, but are less so today.

The BBC World Service has produced a Basic Christianity web page that is well done, though not specifically Anglican.

A Beginner's Guide to the Anglican Church. You'll find the basics of Christian belief, Anglican understanding, what happens in church, and a brief glossary of terms. The Beginner's Guide is from the Church of St John the Evangelist, Roslyn, New Zealand, but is general enough to be useful throughout the communion.