Book readers for mobile phones

BookReader by Tequilacat
Supported phones: Any Java-enabled
MicroReader
Supported phones: Siemens
ReadManiac
Supported phones: Any Java-enabled
mbReader
Supported phones: Any Java-enabled
mjBoook
Supported phones: Any Java-enabled

Online libraries

Project Gutenberg
Project Gutenberg is the Internet's oldest producer of FREE electronic books (eBooks or eTexts)