Adobe® Digital Editions software allows you to download and purchase digital content, which can be read both online and offline. Transfer copy-protected (DRM) e-books from your personal computer/laptop to other computers or devices. ADE also supports industry-standard eBook formats, including PDF and EPUB. NOTES: (1) This software is required to read public library books and some JHU e-books. (2) On iDevices, ADE and BlueFire *must* use the same Adobe ID.
Bluefire Reader is a free app available for iPhone, iPad, iPod touch, and Kindle Fire. This app allows you to view DRM PDF'sand epub formats. NOTE: This app lets you download even DRM-protected books (like those in EBL) directly to your iDevice, without having to use Adobe Digital Editions (ADE).
Calibre is free downloadable software that will sync to your e-device and convert, organize, and generally help you to manage your e-book collection. It allows you to convert e-book formats to read on different e-reader devices. Here is the FAQ: http://tinyurl.com/6462mz5.