Official Latin from the 1969 & 2002 Roman Missals
Communicántes, et memóriam venerántes, in primis gloriósæ semper Vírginis Maríæ, Genetrícis Dei et Dómini nostri Iesu Christi: sed et beáti Ioseph, eiúsdem Vírginis Sponsi, et beatórum Apostolórum ac Mártyrum tuórum, Petri et Pauli, Andréæ, [Iacóbi, Ioánnis, Thomæ, Iacóbi, Philíppi, Bartholomaéi, Matthaéi, Simónis et Thaddaéi, Lini, Cleti, Cleméntis, Xysti, Cornélii, Cypriáni, Lauréntii, Chrysógoni, Ioánnis et Pauli, Cosmæ et Damiáni] et ómnium Sanctórum tuórum; quorum méritis precibúsque concédas, ut in ómnibus protectiónis tuæ muniámur auxílio.
Official 1973 I.C.E.L. Translation (Used at Mass in English)
In union with the whole Church we honor Mary, the ever-virgin mother of Jesus Christ our Lord and God. We honor Joseph, her husband, the apostles and martyrs Peter and Paul, Andrew,
[James, John, Thomas, James, Philip, Bartholomew, Matthew, Simon and Jude; we honor Linus, Cletus, Clement, Sixtus, Cornelius, Cyprian, Lawrence, Chrysogonus, John and Paul, Cosmas and Damian]
and all the saints. May their merits and prayers gain us your constant help and protection.
(Yes, in the English Sacramentary, the optional text is made much smaller. No wonder it doesn't get read!)
Better Literal Translation (based on the Credo translation)
In communion with, and reverently remembering, in the first place, the glorious ever-Virgin Mary, Mother of our God and Lord Jesus Christ: then blessed Joseph, spouse of the same Virgin, and Your blessed Apostles and Martyrs, Peter and Paul, Andrew, [James, John, Thomas, James, Philip, Bartholomew, Matthew, Simon and Thaddeus, Linus, Cletus, Clement, Sixtus, Cornelius, Cyprian, Lawrence, Chrysogonus, John and Paul, Cosmas and Damian], and all Your Saints; by whose merits and prayers grant that we may be strengthened in all things by the help of Your protection.
Their entry in the Roman Martyrology is:
2004 Roman Martyrology
Romæ, commemorátio sanctórum Ioánnis et Pauli, quorum nómini basílica dicáta est in monte Cǽlio ad clivum Scáuri, in titulo Pammáchii senatóris.
My rough translation
At Rome, the commemoration of Saints John and Paul, of whose names a basilica is dedicated on the Caelian mountain [one of the 7 hills of Rome] at the hill of the Scauri, in the title of Senator Pammachius.
The basilica was built over Saint John's and Saint Paul's house.
It is also the place where they were martyred. There is a special marking on the floor of the basilica over the spot on which they were martyred.
The Pammachius mentioned in the Martyrology entry is Saint Pammachius, who was a devout Roman senator who had the basilica built. His relics are also in the basilica.
The relics of Saints John and Paul are in a sarcophagus in the main altar.
I believe the painting behind the high altar is of the Martyrdom of Saints John and Paul.
More information on Saints John and Paul available at the Catholic Encylopedia and separately on the Patron Saint's Index for Saint John and Saint Paul.