the usual conditions are these -
A plenary indulgence can be gained only once a day. In order to obtain it, the faithful must, in addition to being in the state of grace:
—have the interior disposition of complete detachment from sin, even venial sin;
—have sacramentally confessed their sins;
—receive the Holy Eucharist (it is certainly better to receive it while participating in Holy Mass, but for the indulgence only Holy Communion is required);
—pray for the intentions of the Supreme Pontiff.
It is appropriate, but not necessary, that the sacramental Confession and especially Holy Communion and the prayer for the Pope's intentions take place on the same day that the indulgenced work is performed; but it is sufficient that these sacred rites and prayers be carried out within several days (about 20) before or after the indulgenced act. Prayer for the Pope's intentions is left to the choice of the faithful, but an "Our Father" and a "Hail Mary" are suggested. One sacramental Confession suffices for several plenary indulgences, but a separate Holy Communion and a separate prayer for the Holy Father's intentions are required for each plenary indulgence.
Here is some more information on Divine Mercy Sunday, taken from "DivineMercySunday.com"
Plenary Indulgence for Divine Mercy Sunday
In a decree dated August 3, 2002, the Apostolic Penitentiary announced that in order “to ensure that the faithful would observe this day (Divine Mercy Sunday) with intense devotion, the Supreme Pontiff himself established that this Sunday be enriched by a plenary indulgence…so that the faithful might receive in great abundance the gift of the consolation of the Holy Spirit. In this way, they can foster a growing love for God and for their neighbor, and after they have obtained God’s pardon, they in turn might be persuaded to show a prompt pardon to their brothers and sisters.”
The plenary indulgence is granted (under the usual conditions of a sacramental confession, Eucharistic communion and a prayer for the intentions of the Supreme Pontiff) to the faithful who, on Divine Mercy Sunday, in a spirit that is completely detached from the affection for a sin, even a venial sin, recite the Our Father and the Creed, and also adding a devout prayer (e.g. Merciful Jesus, I trust in you!).
Additional provisions are offered for those who are impeded from fulfilling these requirements, but who wish to acquire a plenary indulgence. The full text of the decree of the Apostolic Penitentiary may be found at: www.mercysunday.com. While the readings and prayers for Mass on this day remain unchanged (they reflect perfectly on Our Lord’s Divine Mercy) the Holy See offers this reflection:
The Gospel of the Second Sunday of Easter narrates the wonderful things Christ the Lord accomplished on the day of the Resurrection during His first public appearance: “On the evening of that day, the first day of the week, the doors being shut where the disciples were, for fear of the Jews, Jesus came and stood among them and said to them, ‘Peace be with you.’ When He had said this, He showed them His hands and His side. Then the disciples were glad to see the Lord. Jesus said to them again, ‘Peace be with you. As the Father has sent Me, so even I send you,’ and then He breathed on them, and said, ‘Receive the Holy Spirit. If you forgive the sins of any, they are forgiven; if you retain the sins of any, they are retained’” (Jn 20, 19-23).
In addition, the decree requires that parish priests “should inform the faithful in the most suitable way of the Church’s salutary provision. They should promptly and generously be willing to hear their confessions. On Divine Mercy Sunday, after celebrating Mass they should lead the prayers that have been given above and they should also encourage the faithful to perform acts of mercy as often as they can.”
Today, April 11th is also the feast of Saint Gemma Galgani, so remember to ask for her prayers today as well, and say some prayers in her honor.
