Torsten

http://www.gutenberg.org

http://www.bartleby.com/

More,

http://www.independent.org/

http://www.econlib.org/

http://www.archive.org

onlinebooks.library.upenn.edu

www.yamaguchy.netfirms.com

Well, another, more Kinsellian way of acquiring e-texts is to acquire a safe file-sharing program (I recommend Soulseek, which filters out entirely potentially damaging file suffixes) and then, whilst requiring much patience on the part of the fileseeker, utilizing the search features of the software, search for ".pdf" or ".doc" or whichever you prefer and then scan through your results for anything that might appeal.

This is the mode most like fishing.  It's not ideal, but I've found some real gems.  .pdf files that were purchased from Springer, Oxford, Cambridge, or Amazon and thus otherwise unavailable to the casual fileseeker.

GoogleBooks is a Godsend as well.  With scant exception, most of the pre-1923 publications I've sought out and even some I didn't I've been able to acquire.  The regular Google search engine can work wonders too, if you know the book you're looking for, or a subject, sometimes entering the book's name and filetype:pdf yields results.  

Human Rights Watch, while generally offering statist policy proscriptions, offers many (I would say most) of their publications for .pdf download, and they're certainly quite useful for ascertaining knowledge of (sometimes) obscure global conflicts and a greater understanding of all of the players involved.  If you're a John Denson or vehemently anti-imperial sort of Misesian scholar, Human Rights Watch is a great place to stop for .pdf e-texts.

As you can see, I'm biased towards .pdf documents.  I think they're easily the most ideal and they're convertible for the most part as well.  Bartleby and Gutenberg aren't fond of Adobe apparently, their typesets are hideous, frankly, and virtually all of what they have to offer are available elsewhere in a presentation more conducive to aesthetic sensibility and readability.  

http://www.fee.org/library