This page contains a selection of hardware, software and information resources relating to the ePUB format and ePUB eBooks. It is not necessarily complete, but it is a good starting-point.
The only reference eBook reader for iBooks is the Apple iPad, with the iBooks app installed from the Apple App Store. If you want to distribute your eBooks for iOS devices you must have access to a physical iPad for testing. You will also need access to an iPhone or iPod Touch if you expect your books to be read on these smaller devices. You can install ePUB eBooks on these devices with Apple iTunes. Just connect the device to your computer and drag the ePUB file onto the iPad entry in the iTunes window.
It's a good idea to have access to the physical hardware readers you are targeting for testing. Some have more limited capabilities than others.
The reference software reader is the free Adobe Digital Editions. Before trying to create ePUB eBooks you should download this free reader from Adobe and install it. If you don't do this you won't be able to view your ePUB eBooks on your Windows computer after creating them with Help+Manual. ADE generally provides a good idea of how your eBook is going to look on software readers.
The most up-to-date list of ePUB resources is available on this page on Wikipedia:
The following hardware readers currently support ePUB eBooks, either directly or with free additional software. The most notably absent device on this list at the moment is the Amazon Kindle, which still uses its own closed proprietary format. However, it is rumored that ePUB support for the Kindle is in the works and due to be released in the near future.
Apple iPad, iPhone and iPod Touch
The Sony Reader
Android smartphones and tablets
Other mobile phones and smartphones
Barnes & Noble Nook
Bookeen Cybook Gen3, Cybook Opus
ECTACO jetBook and ECTACO jetBook Lite
iRex Digital Reader 800, 1000
GNU/Linux tablets and PDAs such as Sharp Zaurus and Nokia 770, n800, n810, and n900
Software readers for ePUB eBooks are already available on many platforms. The following list only includes the known software-based readers that support the ePUB format at the time of writing – others may already be available.
The reference software reader is Adobe Digital Editions, this is the one you should get for testing.
Adobe Digital Editions (Windows, Apple OS X)
Lexcycle Stanza (Windows, iPhone, iPod Touch)