The Latin Library: Christian Latin
Online versions of various Christian Latin texts, from Tertullian to Thomas à Kempis.
Primary Sources
Corpus Scriptorum Latinorum
The Forum Romanum website provides a list of Latin literature online, both texts and translations, and includes patristic authors.
EWTN Patristics Library
Another site from which ANF and NPNF may be downloaded. Prefatory notes indicate that EWTN has corrected the texts; they may be more accurate than those posted to other sites.
New Advent: Fathers of the Church
This archive has e-texts of Ante-Nicene Fathers (ANF) and Nicene and Post-Nicene Fathers (NPNF) arranged alphabetically.
Early Church Fathers (Calvin College)
An archive containing all volumes (less indices) of the Ante-Nicene Fathers (ANF) and Nicene and Post-Nicene Fathers (NPNF) in searchable format. All works can be freely viewed online, downloaded for free as text files, or downloaded as pdfs for a fee.