Here are some useful links:

• The United States Conference of Catholic Bishops Vocations Page
  
• The Council of Major Superiors of Women Religious
• Vocation Boom

Suggested Reading:

• John Paul II on the Formation of Priests
• John Paul II on the Consecrated Life
• Story of a Soul by St. Therese of Lisieux
• Confessions by St. Augustine
• Personal Vocation: God Calls Everyone by Name by Germain Grisez and Russell Shaw
• The Soul of the Apostolate by Dom Jean-Baptiste Chautard
• The Priest is Not His Own by Archbishop Fulton J. Sheen
• Treasure in Clay: the Autobiography of Fulton J. Sheen
• Priests for the Third Millennium by Cardinal Timothy Dolan
• A Priest Forever: the Life of Father Eugene Hamilton by Fr. Benedict J. Groeschel, CFR
• When God Asks for an Undivided Heart by Father Apostoli
• The Unchanging Heart of the Priesthood by Fr. Thomas Acklin, OSB
• What Does God Want?: A Practical Guide to Making Decisions by Fr. Michael Scanlan, TOR
• Divine Intimacy: Meditations on the Interior Life for Every Day of the Liturgical Year by Fr. Gabriel
• Self Abandonment to Divine Providence by Jean Pierre de Caussade
• Trustful Surrender to Divine Providence: The Secret to Peace and Happiness by Jean-Baptiste Saint-Jure and Saint Claude de la Colombiere
• Searching for and Maintaining Peace: A Small Treatise on Peace of Heart by Fr. Jacques Philippe
• About Being a Priest by Federico Suarez