I saw the following on another list:
Loading books into the BARDmobile app

The BARDmobile app is able to play any DAISY/NISO 2005 formatted book. 
To load the books into the iOS device for playback use the following 
instructions.
1. If not in a ZIP archive format. You should compress the directory 
holding the books files into a ZIP file.
2. Connect the iOS device to your computer with a USB cable.
3. Open the iTunes application and select the iOS device button at the 
right of the main window.
4. select the "Apps" radio button on the main screen.
5. At the bottom of the Apps screen is a section titled "File Sharing" 
with a column list of apps. One of those will be the BARDmobile app 
select it.
6. Press the "Add…" button located in the bottom right of the screen. 
This will give you a dialog to select the ZIP file from step one. The 
book will then be added to the app. You may need to restart BARDmobile 
to see the new book.
NOTE:
  At this time the BARDmobile app will only play DAISY/NISO 2005 books. 
Other DAISY formats such as DAISY 2.02 and ePub 3 will simply fail to load.