As a branch of ethics, we have a research guide on moral education/development at <http://guides.library.duke.edu/ethics> where searches in both the library catalog and databases are suggested.
Spiritual education can be searched in the library catalog at <http://library.duke.edu/catalog/search/Subject-keyword/spiritual%20formation>
A few recent books in this area are:
Reading from the underside of selfhood : Bonhoeffer and spiritual formation
Dahill, Lisa E. (Eugene, Or. : Pickwick Publications, c2009.)
Divinity School Library BR1 .P756 no.95 c.1
Spiritual literacy in John Wesley's Methodism : reading, writing, and speaking to believe
Tolar Burton, Vicki, 1945- (Waco, Tex. : Baylor University Press, c2008.)
Divinity School Library BX8407 .B87 2008
Henri Nouwen and soul care : a ministry of integration
Hernandez, Wil. (New York : Paulist Press, c2008.)
Divinity School Library BX4705.N87 H47 2008
A couple books that seems to cross both moral and spiritual development is:
O'Connell, Timothy E.
Making disciples : a handbook of Christian moral formation
New York : Crossroad Pub., c1998.
Divinity School Library BV1464 .O26 1998
Formation of the moral self
Ven, J. A. van der, 1940- (Grand Rapids, MI : W.B. Eerdmans, 1998.)
Divinity School Library BV1464 .V45 1998
In addition, you may find the Christian education research guide to be helpful <http://guides.library.duke.edu/ministerial>