Six styles of unofficial, public domain ePub logos are now offered by threepress.org for use: ePub logos.
These logos, created by illustrator John McCoy, are being made available to help spread awareness and adoption of the ePub standard. Publishers and booksellers may use them to indicate that they offer ebooks in ePub format; others may use them to illustrate articles or blog posts on ePub. As the logos are public domain there are no restrictions on how they may be used or modified.
David Rothman of TeleRead has previously called for and distributed one unofficial ePub logo. Please use whichever suits your application or taste.
View ePub logos.