I've found a few java applications that can display ebooks on my mobile phone, but the problem is these seem to require that you turn the .jar file into a zip, unzip it, put your book in it, zip it up and change the extension back to jar and then send this to your phone. However, I can't get this to work, and I think it might be related to OS X's zip format.
There are apps for windows that allow you to make these jar files with books in them, but does anyone know of such an app that works in OS X?