ton of different formats:
.aeh (used by Archos eReaders)
.lrx (used by Sony eReaders)
.ibooks (used by Apple eReaders)
.pkg (used by Newton eReaders)
.mobi (used by Amazon Kindle eReaders)
.epub (used by just about everyone else, including Barnes & Noble NOOK eReaders)
There are actually even more formats than those. That’s just a small sample. So, which one should you make?
Well, the only formats you need to create are EPUB and MOBI. Forget the others. EPUB is quickly becoming the industry standard and 90% of the eReaders on the market can open EPUB files. There is also a very simple conversion tool to change your EPUB into a MOBI. So, you really only need to make an EPUB, convert it to MOBI, and your book will be accessible on 99% of the eReaders out there, including NOOK and Kindle.
Build a digital book with EPUB
The open XML-based eBook format
Need to distribute documentation, create an eBook, or just archive your favorite blog posts? EPUB is an open specification for digital books based on familiar technologies like XML, CSS, and XHTML, and EPUB files can be read on portable e-ink devices, mobile phones, and desktop computers. This tutorial explains the EPUB format in detail, demonstrates EPUB validation using Java technology, and moves step-by-step through automating EPUB creation using DocBook and Python.
EPUB (short for electronic publication) is a free and open e-book standard by the International Digital Publishing Forum (IDPF). Files have the extension .epub.