Student Questions: On baptism, part 1

This is the first of several questions regarding baptism.  A student wonders when a soul is regenerated, thinking about John the Baptist leaping in the womb.  As we work through this question, let's consider what each person consists of (body, soul, and spirit), and how life begins.  How integral is the Word of God in our lives?  How do we know an infant is a child of God?  When Peter says, "Baptism now saves you," what did he mean?