Ebooks

General
Authors
Commercial ebooks
Free ebooks
Publishers
Ebook readers
Tools

General

E-Leseratte
cme.at (Ebooks and ebook readers)
HTML and Mobi
Mobi guide

Commercial ebooks

Ciando
Manning

Free ebooks

Gutenberg

Archive.org
Bookyards
Free Computerbooks
Ebook 3000
Free Ebooks
Free Kindle books
Free Techbooks
Getfreeebooks
Manybooks
Mobileread
Online Programming Books
Open Library
Retroread

Ebook readers

Icarus

Authors

Wilhelm Ruprecht Frieling
J├╝rgen Schulze (Nullpapier.de)
Jonas Winner

Tools

Calibre
k2pdfopt (phantastic!)

Publishers

Addison-Wesley
Bookrix
O'Reilly (German)