The Holy Father has granted the Catholic faithful access to a special plenary indulgence for the Year of Faith (from 11 October 2012 to 24 November 2013) in his decree, URBIS ET ORBIS. Before giving you the instructions for obtaining this special plenary indulgence as per the said decree, here's a quick summary of the meaning of indulgence as explained by W.H. Kent of EWTN and simplified by me.
MEANING OF INDULGENCE
An indulgence is the extra-sacramental remission of the temporal punishment due to sin that has been forgiven. Its remission is granted by the Church in the exercise of the power of the keys, through the application of the superabundant merits of Christ and of the saints, and for some just and reasonable motive.
In the Sacrament of Reconciliation, the guilt of sin is removed, and with it the eternal punishment due to mortal sin; but there still remains the temporal punishment required by Divine justice, and this requirement must be fulfilled either in the present life or in the world to come, i.e., in Purgatory. An indulgence offers the penitent sinner the means of dicharging this debt during his life on earth.
A plenary (vs. partial) indulgence offers the remission of the entire temporal punishment due to sin so that no further expiation is required in Purgatory. Note that it presupposes the effects obtained by confession, contrition, and sacramental satisfaction (i.e. the temporal punishment of the sin is discharged by the plenary indulgence only if the sin has been confessed and absolved.) This indulgence is a plenary indulgence.
Some indulgences are granted in behalf of the living only, while others may be applied in behalf of the souls departed. Since the Church has no jurisdiction over the dead, she makes the indulgence available for them by way of suffrage, i.e. she petitions God to accept these works of satisfaction and in consideration thereof to shorten the sufferings of the souls in Purgatory. This indulgence is "applicable in suffrage to the souls of the deceased".
INSTRUCTIONS FOR OBTAINING THE SPECIAL PLENARY INDULGENCE OF THE YEAR OF FAITH (extracted from URBIS ET ORBIS)
Throughout the Year of Faith — established from 11 October 2012 to 24 November 2013 — all individual members of the faithful who are truly repentant, have duly received the Sacrament of Penance and Holy Communion and who pray for the intentions of the Supreme Pontiff may receive the Plenary Indulgence in remission of the temporal punishment for their sins, imparted through God’s mercy and applicable in suffrage to the souls of the deceased:
a. every time they take part in at least three homilies preached or attend at least three lectures on the Proceedings of the Second Vatican Council and on the Articles of the Catechism of the Catholic Church, in any church or suitable place;
b. every time they go as pilgrims to a Papal Basilica, a Christian catacomb, a cathedral church, a sacred place designated by the local Ordinary for the Year of Faith (for example, the Minor Basilicas and Shrines dedicated to the Blessed Virgin Mary, to the Holy Apostles or to the Holy Patrons), and take part there in some sacred function or at least pause in recollection for a suitable length of time with devout meditation, concluding with the recitation of the Our Father, the Profession of Faith in any legitimate form, invocations to the Blessed Virgin Mary or, depending on the case, to the Holy Apostles or Patrons;
c. every time when, on the days determined by the local Ordinary for the Year of Faith (such as, for example, the Solemnities of the Lord and of the Blessed Virgin Mary, the Feasts of the Holy Apostles and Patrons and of the Chair of St Peter), in any sacred place, they take part in a solemn Eucharistic celebration or in the Liturgy of the Hours, adding the Profession of Faith in any legitimate form;
d. a day freely chosen during the Year of Faith on which to make a devout visit to the baptistery or other place in which they received the sacrament of Baptism, if they renew their baptismal promises in any legitimate form.
Diocesan or Eparchial Bishops and those who are legally equivalent to them, on the most appropriate day in this period, on the occasion of the principal celebration (for example, 24 November 2013, on the Solemnity of Our Lord Jesus Christ, Universal King, with which the Year of Faith will end) will be able to impart the Papal Blessing with the Plenary Indulgence from which all the faithful who receive this Blessing devoutly may benefit.