Kobo has 312 free books for you as of March 2011. Most of them are novels, and most of those are by Americans. The books come as either PDFs or Adobe DRM files. While Kobo offers its own application for reading on smart phones, any e-reader will work with PDFs. For the protected Adobe DRM files, you'll need to use the free Adobe Digital Editions software first. You'll need to register before getting a book. With its own application and mainstream titles, Kobo comes across as a legitimate player in the field.
Bibliotastic serves up only free books. It has a clean interface, no ads and apparently no business model. Regardless, it's a joy to use. Register for an account and download to your heart's content. Click on a title that seems interesting to visit its page, then click the download link. It's essentially the same process at all these sites. Ratings by the Bibliotastic editors and readers can help guide you to the most popular choices.
One of the advantages of Smashwords is that the site offers its books in every format imaginable. You can read any novel in proprietary formats, as a PDF or even as text on a webpage. According to the site, 13,000 writers have contributed over 30,000 digital books. Authors price their own books and most are free. To find the free novels, click on any category in the left column and, once there, click on the "Free eBooks" link near the top of the page.
The design of All Books Free hearkens back to the 1990s, but the concept is modern. John Kremer built the site to agglomerate links to free books across the Internet while advertising his book-marketing services. Cory Doctorow, who offers all his books free, is included in the collection. It's a small site but it's definitely worth a visit.