Finding e-books: a guide for devices and formats

Have a look on

http://www.loc.gov/rr/program/bib/ebooks/devicesformats.html

The wide variety of file formats, devices, and dedicated e-readers can be overwhelming. Here is a guide to the range of devices used to access e-books and an outline of common file formats. The list of file formats also includes compatibility with specific devices, where applicable.