The Traditional Latin Mass is the Catholic Mass celebrated according to the Roman Missal promulgated by St. Pius V in 1570 and reissued by Blessed John XXIII in 1962. This form of Mass has come down to us with only slight and gradual changes from the time of St. Gregory the Great in the sixth century. It is distinct in many ways from the Mass celebrated according to the Roman Missal promulgated by Pope Paul VI in 1970.
On July 7, 2007, Pope Benedict XVI issued Summorum Pontificum, an apostolic letter clarifying the status of the 1962 Missal and other traditional sacramental forms. He decreed that the liturgical books in effect in 1962 were never abrogated (negated) and their use remains valid (SP, Art. 1, 9). They are to be considered "extraordinary" forms of the one Roman Liturgy.
Since the 1962 Missal was never abrogated, the rules for its use are largely the same as for the newer Missal. Any qualified priest may say the extraordinary form privately, and the faithful may attend this private Mass (SP, Art. 2, 4, 5.4). The pastor of a parish may add the extraordinary form to the parish schedule, and the bishop may establish parishes or appoint chaplains devoted to its use (SP, Art. 5, 10).
Pastors are directed to provide the extraordinary form when requested by "a group of faithful who stably adhere to the earlier liturgical tradition" (SP, Art. 5.1). They are also urged to grant its use for marriages, funerals, pilgrimages, and other special occasions (SP, Art. 5.3).
In regular parishes, the extraordinary form of Mass may be used only once on Sundays and feast days (SP, Art. 5.2). No private masses of any kind may be said during the Easter Triduum (see SP, Art. 2).
Pastors are encouraged to grant requests for Baptism, Marriage, Penance, and the Anointing of the Sick in their earlier forms (SP, Art. 9.1). Ordinaries are encouraged to administer Confirmation in the traditional form (SP, Art. 9.2.). Any priest may use the 1962 Roman Breviary (SP, Art. 9.3).
Write your pastor or bishop, and mention that your request is in accordance with Summorum Pontificum.