Benedict XVI's Moto Proprio allowing (in effect) the wider use of the ceremonies of the Roman Rite prior to the Second Vatican Council. You can find it here, in Latin or here, in English.
The Holy Father has also written a letter to the Bishops of the world, which can be read here.
The principal teaching is that there is, indeed, only one Roman Rite. The Missal of Paul VI provides the "ordinary form" of the rite, while the Missal of Blessed John XXIII provides the "extra-ordinary form". The 1962 Missal was never abrogated, so it is a legal rite. All that remains then is for the Church to set down the conditions/circumstances in which the rite may be celebrated.
The Motu Proprio, and the letter to the bishops are - as we might expect from Benedict - models of clear thinking, and set forward undertsandable, rational principals. There is no rolling back of the clock here. The validity of Vatican II, and the supremacy of the rite of Paul VI, are explicitly affirmed.
However, there is likely to be much misleading reporting of the letters and what they entail. Take a look at the first report from the BBC. It confuses 'Latin' with the old mass, and makes several statements which are so simplified as to be misleading.
