The World Ebook Fair begins today with free downloads of over 500,000 full-text ebooks from July 4 to August 4.
Most of the books appear to be in the public domain and could be downloaded off the internet for free anyway. Project Gutenberg is an affiliate. You won't find Tom Clancy or Stephen King here. Some recent fiction titles are available from the Baen Science Fiction collection. Those novels are sci-fi and fantasy and some of them seem to be well-regarded by fans of the genres.
It would be a nice touch for giant publishers like Random House or HarperCollins to join a promotion like this and find an out-of-print backlist title to make available, then promote and market their participation while patting themselves on the back for giving away something "for free." Just an idea.