James 5:14-15: "Is any man sick among you? Let him bring in the priests of the church and let them pray over him, anointing him with oil in the name of the Lord. And the prayer of faith shall save the sick man. And the Lord shall raise him up: and if he be in sins, they shall be forgiven him."
The Sacrament "Extreme Unction," also called "Last Rites" or "Annointing of the Sick," is the annointing given to those who are gravely bodily ill, especially those in danger of death from bodily illness or from violence already done to the body (i.e., a soldier about to go into battle is not a candidate for the Sacrament; one who has been shot and lies gravely wounded or, especially, dying, is).
The conditions for receiving Unction are that one must:
The effects of the Sacrament are the strengthening and comfort of the soul of the annointed one, the remission of sins and some of their temporal punishments, and the possible restoration of bodily health.
The Rite in which the Sacrament is offered includes the Sacraments of Penance and the Eucharist (in that order), followed by the Sacrament of Unction itself. It may be received conditionally up to three or four hours after apparent death (we can't presume to know the moment the soul leaves the body and can only know with moral certainty that death has occured after corruption has begun). If the sick one is unconscious, conditional absolution and Unction are offered, without the Eucharist (known at this time as "Viaticum," meaning "Food for the Journey").
The matter of the Sacrament is the Oil of the Sick ("Oleum Infirmorum"), which is olive oil blessed by the Bishop on Maundy Thursday (the Thursday of Holy Week -- the week before Easter).
The form of the Sacrament are the words:
Through this Holy Unction or oil, and through the great goodness of His mercy, may God pardon thee whatever sins thou hast committed by evil use of sight (sight, hearing, smell, taste and speech, touch, ability to walk).
If death is so imminent that there is no time for the full Rite, the Sacrament may be given with a single annointing on the forehead and the words:
Through this holy unction may the Lord pardon thee whatever sins or faults thou hast committed.
The preparations for Extreme Unction are almost precisely like those for receiving a sick call from a priest, but a few extra items are nice to add: bread, cotton, and lemon or salt.
First, prepare the house: Set up a table near the bed in a place where the sick person can see it easily, such as at the foot of the bed or at the side halfway down the length of the bed. Cover it with a white cloth, and on it place the Crucifix and two lit blessed candles, one on each side of the Crucifix. Near them, place a dish of regular water, a bottle of holy water, a clean linen cloth for the priest's fingers, and a piece of palm the priest can use to spinkle the holy water (if you don't have palm, you can use another type of plant, such as box). The following aren't strictly necessary, but the priest may find them useful: cotton or slices of bread, some lemon slices, a dish of salt, and a small bell (to summon family after the sick one's Confession, if necessary). Lay a linen cloth across the breast of the sick person. If you don't have any of the items at all, everything will be okay; these are just the normal way of doing things and are not totally imperative!
Greet the priest at the door: Women should cover their heads; men should uncover theirs. Meet the priest in silence at the door, bearing a lighted blessed candle (preferably the Baptismal candle of the sick one), and genuflect. Lead him to the sick person's room and remain there with him until Confession is heard. When you leave the room while Confession is being heard, close the door; you may re-enter when the priest opens it again. At all times, the priest will be quiet and somber; don't expect him to socialize before or afterward, as he carries with him the Body of Christ.
Copy/pasted from: http://www.fisheaters.com/unction.html