The Ludwig von Mises Institute has made available 1200+ ebooks for your reading pleasure. From the site:
The most complete online offering of the literature of the Austrian School and libertarian ideas, including books, journal articles, and other writings, sorted by author or any method you choose.
We recommend Adobe Reader for PDF files and Adobe Digital Editions for desktop reading of ePub (ebook) files.
For an ePub reader, we recommend the iBook app, O’Reilly’s Bookworm, or the Stanza Catalog.
You can find the collection at http://mises.org/Literature
Enjoy the collection!
Also, be sure to read Murray Rothbard’s Anatomy of the State.