The Law Library has recently acquired access to the Religion Case Reporter - "the only publication in the United States devoted exclusively to reporting and indexing judicial opinions addressing the interaction between law and religion."  The Religion Case Reporter provides summaries and sometimes the full text of these court opinions dealing with religion.  The best part about this resource is its cumulative index that allows researchers to quickly find cases that combine religion and other legal topics.  For example, the entry "adoption" in the index will provide you with several adoption cases that involve religion in some way.