Carnegie Library of Pittsburgh: http://www.clpgh.org/eCLP/Not all are free, but some can be downloaded without a membership cardFree Library of Philadelphia has a large ebook and audio book selection available through Overdrive. PA residents may register for a card at: http://libwww.freelibrary.org/register/getcard1.cfmBooks Should Be Free offers free audio books from the public domain:http://www.booksshouldbefree.com/Open Library: http://openlibrary.org/Google ebookstore: http://books.google.com/ebooksNot all are free, but there is a free sectionProject Gutenberg: http://www.gutenberg.orgThe above websites will open in new windows.