A prayer from the Little Flower:
O Jesus, I pray for Your faithful and fervent priests, for Your unfaithful and tepid priests; for Your priests labouring at home or abroad in distant mission fields; for Your tempted priests; for Your lonely and desolate priests; for Your young priests; for Your dying priests; for the souls of Your priests in purgatory.
But above all I recommend to You the priests dearest to me: the priest who baptized me; the priest who absolved me from my sins; the priest at whose Masses I assisted and who gave me Your Body and Blood in Holy Communion; the priests who taught and instructed me; all the priests to whom I am indebted in any other way. Jesus, keep them all close to Your heart, and bless them abundantly in time and in eternity. Amen.
Here are links to other sites with prayers for priests: