You can search and preview millions of books in Google Books. To find free full-text Google books: Select "Search Tools." Under "Any books" choose, Free Google eBooks. NOTE: Free Google books will mostly include books published before 1923.
Repository of digital content from research libraries including content digitized via the Google Books project and Internet Archive digitization initiatives, as well as content digitized locally by libraries. Only public domain works will be full-text searchable.
A non-profit digital library offering free universal access to books, movies & music, as well as 281 billion archived web pages.
Listing of over 1 million free books on the Web. Browse books by subject heading to find religion and theology links.
Open Library is an open, editable library catalog, building towards a web page for every book ever published. One web page for every book ever published. It's a lofty but achievable goal.