The period between Pope Benedict's resignation (February 28 at 2PM, EST) until the election of his successor later this month is know as "Sede vacante", literally with the Chair [of St. Peter] vacant.
Instead of the papal coat of arms being posted on Vatican letterhead, buildings, etc., the above heraldic representation is used. Let us rememeber to keep Pope Benedict in our prayers, as well as the Cardinals who will begin their sessions and congregations tomorrow morning and afternoon until they are ready to set a date for the Conclave to start.
Here is a prayer provided by the Knights of Columbus that is suitable for this period:
O Lord Jesus Christ, Supreme Pastor of Your Church, we thank you for the ministry of Pope Benedict XVI and the selfless care with which he has led us as Successor of Peter, and Your Vicar on earth.
Good Shepherd, who founded Your Church on the rock of Peter’s faith and have never left Your flock untended, look with love upon us now, and sustain Your Church in faith, hope, and charity.
Grant, Lord Jesus, in Your boundless love for us, a new Pope for Your Church who will please You by his holiness and lead us faithfully to You, who are the same yesterday, today, and forever. Amen.