Ambrose, Saint - http://www.bartleby.com/65/am/Ambrose.html Biographical entry in the Columbia Encyclopedia. Includes short bibliography.
Ambrose of Milan, Bishop and Doctor - http://elvis.rowan.edu/~kilroy/JEK/12/07.html Brief biography, with some asides on Arianism, and prayer in traditional and contemporary language.
The Ecole Initiative: Ambrose of Milan - http://www2.evansville.edu/ecoleweb/articles/ambrose.html Article on the career of St. Ambrose, by Ivor J. Davidson. Includes an extensive bibliography.
Catholic Encyclopedia: St. Ambrose - http://www.newadvent.org/cathen/01383c.htm Article on the life and teachings of this Bishop of Milan, and Doctor of the Church, who died in 397.
Prologomena to St. Ambrose - http://www.ccel.org/ccel/schaff/npnf210.toc.html From the Nicene and Post-Nicene Fathers of the Christian Church, second series, vol. 10. Introduction to the life and writings of St. Ambrose, with a timeline.
Lives of Saints: Ambrose of Milan - http://saints.sqpn.com/sta07001.htm Profile of this bishop, confessor, and Doctor of the Church. From the book "Lives of Saints," published by John J. Crawley.