For the first time in about 600 years, a Pope has left the Chair of St. Peter by resignation rather than death. Pope Benedict startled the world this morning by announcing that he will be retiring from the papacy at the end of the month. This move was likely taken with much prayer and discernment by the Holy Father, as discussed in this article by William Fahey.
As can be expected, there is much speculation on who the papal successor would be. I have no clue as to who that may be, but I believe the Holy Spirit will guide the selection toward someone able to lead the Church with vigor and moral clarity in proclaiming Jesus Christ in the face of hostility from much of our contemporary culture.