Bibliotastic , a site for self-publishing authors, launched about a month ago. This is not an eBookstore, surprisingly. It’s not selling anything; instead its goal is to be the best source for free, contemporary, ebooks on the web. It wants to take on the same role for ebooks that YouTube has for video.
Supported formats include PDF, Epub, and Mobi., and there is no DRM on the eBooks.
The site is also running a contest at the moment, and it will make you chuckle. You can enter the contest by leaving a comment on an eBook, and the prizes include an apple (first prize) and some kindling (25 runners-up).