The Sacrament of Holy Orders is referred to as a mission entrusted by Christ to his apostles until the end of time (MT 28:18-20). God continually calls men to serve in the Church as either a deacon or priest. There are three degrees of Holy Orders: Episcopate (Bishop), Presbyterate (Priest), and Diaconate (Deacon).
The process to ordination begins when a man feels the call in his soul and confers with a spiritual director, parish Priest, or vocation director, who then refers him to the proper ecclesiastical authorities. Upon approval of the Bishop (Diocesan Priesthood Candidate) or Religious Order Superior (Religious Priesthood candidate), the Candidate begins the formal education required by Canon Law for ordination. Dioceses and Religious Orders use various universities and seminaries for their candidates to Orders.
Any man who feels a call to the priesthood should speak to his parish priest and ought to visit the Diocese of Harrisburg's website for more contact information.