Electronic reading devices--eReaders--were a popular gift item this holiday season. People have been coming in asking for tips on how to download electronic library books to their new eReaders, and circulation has skyrocketed. Fantastic!
Others have expressed dismay that their brand of eReader won't accept library books. Yes, only the Barnes and Noble Nooks, the Sony Readers, the Kobo eReader, Literati Reader, Pandigital Novel, and Pocketbook Pro accept our OverDrive ebooks.
By the way, the Digital Media catalog also stocks electronic formats for reading on various computers and listening to on a number of audio devices. 
One of my favorite librarian bloggers just posted a link to this beginner's guide to electronic formats. I hope it's useful. http://bookbee.net/bee-ginners-guide-2/