I’m a card-carrying member of my public library and recently found that using Adobe’s OverDrive on my iPad allows me to download both audio files and pubs to read or listen to on the iPad [and iPhone]. Ironically, no Flash is required! OverDrive is a media console which you can download free at the iTunes App Store.
You then go to to ‘Get Libraries’ and search for the library you want by name, city or zipcode. You need to have a library card/membership (and have your number with you since it’s not saved & needs to be entered each time]. Once you do login with your library number, you are sent to the online link where you can download books to read/listen to over a set span of days [7 days in the case of something I selected]. You can add a book to a wish list, or place a hold on it and you’ll get an email alerting you to its availability with a window of two days to download. But, the app also gives you access [as do many others] to free ebooks [most of which are through the Gutenberg Library project].
OverDrive provides a way to view the epub or listen to it. There certainly are a number of reading/listening apps out there, but this one is specifically linked into the downloadable content of the nation’s public libraries.