Actually, protected epub books can be downloaded directly to the PE using the Overdrive app. My local library's website had the link for installing Overdrive. For initial setup, you do have to install Overdrive on a PC, but once the app is installed on the PE, use of a PC is not required.
I add books regularly by clicking on the "Get New Books" link in the Overdrive program, which takes me to one of the libraries links that I have added to my favorite library list (note: you do have to have an account at that library). I currently browse and add books from 4 libraries. When I select a book and add it to my cart, I can then click the download link on the PE and directly download and open the book on the PE. I do not need to download the books to my PC. The process is very simple through my libraries....if I am on a waiting list for a particular book, I receive and e-mail when the book is ready for me, and can download the book to the PE by clicking on the e-mail link. Couldn't be any easier!
In addition to new-release books, each library also has a large inventory of non-protected books that can also be downloaded.
I would suggest taking a look at your local library's website to see their process for getting e-books.
Here is the link to the Ohio Library Consortium which discribes the process and may have some answers to your questions;
http://ohdbks.lib.overdrive.com/A234...en/Default.htm