The Antichrist  
   E-text of the Mencken translation.
   http://www.fns.org.uk/ac.htm

On the Use and Abuse of History for Life  
   E-text of the Johnston translation.
   http://www.mala.bc.ca/~johnstoi/Nietzsche/history.htm

Thus Spake Zarathustra  
   E-text of several versions from Project Gutenberg.
   http://digital.library.upenn.edu/webbin/gutbook/lookup?num=1998

Thus Spoke Zarathustra  
   Audiobook downloadable for free in mp3 format.
   http://www.audiobooksforfree.com/download/default.asp?refnum=1000079

Twilight of the Idols  
   E-text of the Kaufmann/Hollingdale translation.
   http://www.handprint.com/SC/NIE/GotDamer.html

The Prejudices of Philosophers  
   The first chapter of Nietzsche's 1885 work Beyond Good and Evil. As translated by Helen Zimmern.
   http://www.marxists.org/reference/subject/philosophy/works/ge/nietzsc1.htm

Beyond Good and Evil  
   A complete English translation of this work, compiled from the Zimmern and Kaufmann translations.
   http://www.geocities.com/thenietzschechannel/bge.htm

Thoughts Out Of Season  
   E-text, Part One.
   http://www.ibiblio.org/HTMLTexts/Friedrich_Wilhelm_Nietzsche/Thoughts_Out_Of_Season_Part_One/

Free Online Library - Thus Spake Zarathustra: A Book For All And None  
   Details Nietzsche's views and philosophies as told through Zarathustra, who has come down from a mountain in order to offer his wisdom to the world.
   http://Nietzsche.thefreelibrary.com/Thus-Spake-Zarathustra

Theory of Knowledge  
   Brief essay on the philosopher's epistemology, comparing it to Ludwig Wittgenstein and Thomas Kuhn.
   http://huizen.daxis.nl/~henkt/nietzsche-theory-of-knowledge.htm

Also Sprach Zarathustra  
   Interpretative summary of the work.
   http://huizen.daxis.nl/~henkt/also-sprach-zarathustra.htm