1st Books Library About 3,000 online books, some of which are free. Various formats

Christian Classics Ethereal Library Large collection of Christian and theological books in different formats

New Desiring God eBooks John Piper's Books online and free/p>

Fire and Ice  Primarily excerpts and shorter works of Puritan and Reformed writers

Project Gutenberg Strong in classics, literature and reference books in plain text and ZIP formats

Reformed Books and Commentaries  Includes works by Owen, Machen and Calvin

The Online Books Page Some 10,000 titles from diverse sources in a variety of formats