The Vatican Radio website has the full text of the pope's statement today. Here it is in full:
Dear Brothers,
I have convoked you to this Consistory, not only for the three canonisations, but also to communicate to you a decision of great importance for the life of the Church. After having repeatedly examined my conscience before God, I have come to the certainty that my strengths, due to an advanced age, are no longer suited to an adequate exercise of the Petrine ministry.
I am well aware that this ministry, due to its essential spiritual nature, must be carried out not only with words and deeds, but no less with prayer and suffering. However, in today’s world, subject to so many rapid changes and shaken by questions of deep relevance for the life of faith, in order to govern the bark of Saint Peter and proclaim the Gospel, both strength of mind and body are necessary, strength which in the last few months, has deteriorated in me to the extent that I have had to recognise my incapacity to adequately fulfil the ministry entrusted to me.
For this reason, and well aware of the seriousness of this act, with full freedom I declare that I renounce the ministry of Bishop of Rome, Successor of Saint Peter, entrusted to me by the Cardinals on 19 April 2005, in such a way, that as from 28 February 2013, at 20:00 hours, the See of Rome, the See of Saint Peter, will be vacant and a Conclave to elect the new Supreme Pontiff will have to be convoked by those whose competence it is.
Dear Brothers, I thank you most sincerely for all the love and work with which you have supported me in my ministry and I ask pardon for all my defects. And now, let us entrust the Holy Church to the care of Our Supreme Pastor, Our Lord Jesus Christ, and implore his holy Mother Mary, so that she may assist the Cardinal Fathers with her maternal solicitude, in electing a new Supreme Pontiff. With regard to myself, I wish to also devotedly serve the Holy Church of God in the future through a life dedicated to prayer.
From the Vatican, 10 February 2013
BENEDICTUS PP XVI
Coat of arms for Pope Benedict XVI. 
With news of Pope Benedict XVI's resignation only hours old, online gambling sites have already published odds for who will become the next leader of the Roman Catholic Church, with   and  as early odds-on favorites.

Online Australian gambling site SportsBet has Canadian Cardinal Marc Ouellet as their favorite with 7/2 odds. The Irish  brokers has 11/4 odds with the Canadian Cardinal being chosen as Pope. Bwin has Ouellet becoming the next Pope with odds at 7/2. British SportingBet also has odds for Ouellet at 7/2.

British  has Nigerian Cardinal  with 7/2 odds. 

 has the betting odd for Ghanian Cardinal Peter Kodwo Appiah Turkson at 7/2, its best odds for any potential Papal candidate.  BetVictor also has the best odds on Turkson with 5/2.  Stan James has the best odds for Turkson at 3/1. You Win has odds for Turkson at 5/2.

Bets are also being taken by Paddy Power for the name of the next Pope, with Peter their odds-on favorite at 2/1.  It is followed by Pious at 5/1, and John Paul and John at 6/1.