This response is over kill but there is a list included that should provide you with various sources of books - purchasable and free.
When you purchase a book or download one from your local library you will have to make sure that they use Adobe Digital Editions (ADE) DRM for ePub or PDF. Usually on checkout you will be supplied with a file that you will download to your PC. Then if you click on that file and everything is setup properly it will start up Digital Edition which will then download the book and add it to it's bookshelf.
Then you can transfer that book to your Libre via USB2 and ADE.
****** Note:ADE is a free program that you download from adobe and install on your PC. It becomes one of your ebook managers as well as the authenticator for purchased books. The Aluratek Libre Pro uses ADE to manage DRM controlled books on your unit as well as your PC. You can read your books on your PC using ADE as well.
****** When purchasing from Online stores such as Barns and Noble you have to be careful that the book is available as ADE-ePub as there are other ePub DRM formats that are not compatible with ADE.
****** Note: if you do not want to keep DRM in play there are methods that you can use to remove the DRM so that in the future you can read the ebook on any other ereader that supports that book's format. This allows you to use ebooks that you purchase on ereaders that do not support DRM such as the Ectaco JetBook (The JetBook-lite supports B&N DRM).
This is a selection of what I have gathered since my involvenment with e-books and e-readers.
Here is my text file on resources for ebooks and ereaders
Various Formats and e-Readers explained:
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http://en.wikipedia.org/wiki/E_Ink
http://en.wikipedia.org/wiki/Transreflective_LCD
http://en.wikipedia.org/wiki/LCD_backlight
http://en.wikipedia.org/wiki/LCD
http://ebookarchitects.com/conversions/formats.php
http://en.wikipedia.org/wiki/Ebook
http://en.wikipedia.org/wiki/Compari...e-book_formats
http://en.wikipedia.org/wiki/List_of_e-book_readers
https://www.mobileread.com/forums/
Both wikipedia as well as mobileread contain direct links to vendors of ereaders, ebook sources, reviews, Format converters, forums, how too's and PC base ebook readers/manager software.
My firsthand notes on the following two readers:
http://www.aluratek.com/product_info...02&display=All
http://www.jetbook.net/
Note: jetBook and Aluratek Libre Pro are identicle hardware device offered by two different companies. The Aluratek offers ePud and PDF DRM via Adobe Digital Editions. The jetBook only offers DRM through it's jetBook-Lite variant (powered by 4 AA batteries).
Aluratek handles PDF documents better by allowing "Text Flow" to be turned on or off. In the Off set-up the PDF doc is displayed the same way on both readers.
**** Update June 24-2010 ****
Within this forum is a new firmware for the Ectaco jetBook (regular model) - Firmware .35a that gives the jetBook ADE DRM ePub/PDF support now as well a TOC support in both ePub and PDF documents. You also get "Text Flow" support for reading PDF documents.
You lose Dictionary support within ePub as well as the search or find option within an open ePub book.
******* End of Update *************
The jetBook offers a built in dictionary look-up for words within an open book. It also offers translation of the selected word between Russian, German, Spanish and Polish with English as the common source. The only problem is that the English dictionary is weak - Having english and my main language I found that most words that I search on were not in the dictionary's database.
Both readers offer only 2 font styles and 6 levels of size within each font.
Custom fonts are only available when built in to a PDF document.
Related Links, Blogs and Forums:
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http://calibre-ebook.com/
http://indiekindle.blogspot.com/
http://www.kindle-pages.com/
http://www.teleread.com/
http://www.thekindlechronicles.com/
http://www.bookspot.com/ask/
http://www.ereaderforum.com/forum/
http://wolfmont.com/wordpress/?p=143
http://apprenticealf.wordpress.com/
http://igorsk.blogspot.com/2007/12/m...on-kindle.html
http://i-u2665-cabbages.blogspot.com/
Links to various sources of free & non-free e-books:
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http://www.gutenberg.org/wiki/Main_Page
http://www.baen.com/library/
http://booksontheknob.blogspot.com/
http://www.bookyards.com/
http://www.bygosh.com/thebestnovels.htm
http://www.digitalbookindex.org/about.htm
http://www.ebooks3.com/
http://www.feedbooks.com/
https://www.fictionwise.com/ebooks/freebooks.htm
http://www.free-online-novels.com/
http://www.free-ebooks.net/
http://www.literaturecollection.com/
http://manybooks.net//
http://www.outpost19.com/
http://delicious.com/pd_workman/kindle
http://www.online-literature.com/
http://onlinebooks.library.upenn.edu/
http://www.bl.uk/onlinegallery/ttp/ttpbooks.html
http://www.webscription.net/
http://www.webscription.net/
http://www.omnilit.com/category234_3.html
http://www.smashwords.com/
http://www.kobobooks.com/
http://infomotions.com/alex/
http://digital.library.upenn.edu/wom...html#B_Section
http://www.bibliomania.com/
http://www.classicreader.com/
http://www.ebooklobby.com/
http://www.balajisebookworld.com/page_1.html
http://www.starry.com/novel/authors.htm
http://www.borders.com/online/store/...185&kids=false
http://www.amazon.com/
http://www.literaturemaster.com/
http://lib.virginia.edu/digital/coll...g_digital.html
http://www.fictionpress.com/
http://www.life-after-harry-potter.com/
http://www.literature.org/
https://wiki.mobileread.com/wiki/E-book_stores
http://www.thefreelibrary.com/
http://www.readprint.com/
http://www.readbookonline.net/
http://www.truly-free.org/
http://www.worldwideschool.org/libra...bject-top.html
The End - enjoy