Bibliography on evangelization from the USCCB Secretariat for Evangelization:
United States Conference of Catholic Bishops

Texts of documents from recent popes:
The Vatican

Ministry to returning Catholics:
Landings International

Ministry to returning Catholics:
Once Catholic

Ministry to teenagers:
Cultivation Ministries

Ministry to young adults:
Busted Halo

Helpful databases and statistics:
Center for Applied Research in the Apostolate (CARA)

The Paulist Fathers

Paulist Vocations