On-Line Texts Related to Biblical Study: Nag Hammadi Collection
A large collection of online texts.
http://ccat.sas.upenn.edu/~humm/Resources/Texts/nagHam.html

Apocryphon of John - Wikipedia
An article detailing this Gnostic text.
http://en.wikipedia.org/wiki/Apocryphon_of_John

Apocalypse of Adam - Wikipedia
A summary of this text and the Gnostic implications.
http://en.wikipedia.org/wiki/Apocalypse_of_Adam

The Thunder, Perfect Mind - Wikipedia
A poem discovered among the Gnostic manuscripts at Nag Hammadi in 1945.
http://en.wikipedia.org/wiki/The_Thunder_Perfect_Mind

Trimorphic Protennoia - Wikipedia
A Sethian Gnostic text from the New Testament apocrypha.
http://en.wikipedia.org/wiki/Trimorphic_Protennoia

The Gospel of Thomas Collection -- The Gnostic Society Library
The Gospel of Thomas in multiple translations, along with a vast collection of material about the Thomas tradition. Includes the entire Hammadi Library, as well as a large collection of other primary Gnostic scriptures and documents.
http://www.gnosis.org/naghamm/nhl_thomas.htm

The Hymn of the Pearl - The Acts of Thomas
Part of a library of materials dealing with Gnosis and Gnosticism, both ancient and modern.
http://www.gnosis.org/library/hymnpearl.htm

Zostrianos -- The Nag Hammadi Library
Zostrianos, from The Nag Hammadi Library.
http://www.gnosis.org/naghamm/zostr.html

The Gospel of the Egyptians -- The Nag Hammadi Library
The Gospel of the Egyptians, from The Nag Hammadi Library.
http://www.gnosis.org/naghamm/goseqypt.html

The Judas Gospel - National Geographic Magazine
Excepts of this Gospel courtesy of National Geographic.
http://www7.nationalgeographic.com/ngm/gospel/index.html

Gospel of Judas
The Gospel in PDF format.
http://www.nationalgeographic.com/lostgospel/_pdf/GospelofJudas.pdf

The Gospel of Mary
This Gospel in PDF format.
http://www.gnosticjudas.com/gospels/EN_The_Gospel_of_Mary.pdf

Mandaean Gnostic Texts
Rare Mandaean Gnostic texts.
http://www.egnu.org/~mandaean/

Gist of Gnostic Texts
Various Gnostic texts in html format.
http://oaks.nvg.org/pv3bk9.html