Catholic Online has a special mini-site for Advent here. Here's a sample.
The readings in the Liturgy of the Hours throughout this Advent season will orient us to prepare for the coming(s) of the Lord. They will challenge us to examine our lives and clear out any obstacles to the working of His grace within us and then through us in the lives of others. This time of preparation for the Nativity, the First coming and time of anticipation of the Parousia, the Second Coming, is to be lived by us as men and women signed with the Cross who are wide awake, at the ready, always looking for His coming. The excerpts from the treasury of writings in the Christian Tradition will emphasize this theme of watchfulness. We begin on the First Sunday of Advent with an excerpt from an ancient homily from St. Cyril of Jerusalem entitled “The Twofold Coming of Christ: “We do not preach only one coming of Christ, but a second as well, much more glorious than the first. The first coming was marked by patience; the second will bring the crown of a divine kingdom.