The Archbishop of Canterbury visits Pope Benedict XVI today.
His Grace’s meeting with His Holiness was previously scheduled to but certainly follows the extraordinary announcement of the 5 Anglican bishops desire for entering into full communion with the Church of Rome. Ostensibly Williams was in Rome to participate in the 50th anniversary celebrations of the Pontifical Council for Promoting Christian Unity but exact details of the discussion with the Pope are not public (yet?).
The Vatican Radio report carries more information.