One of my favourites is smashwords, http://www.smashwords.com/
this has some free ebooks, and some for a modest fee. They are all by independant authors, and all are DRM Free.
They are normally availiable in formats for most Ebook readers, including EPUB for stanza, LRF for Sony, PFD, and Kindle, plus others.
Authors can also upload there own works, formatted in line with the styleguide, and run them through the Smashwords meatgrinder to provide them in all the formats, so they can sell them, or disribute them for free.
My first novelette, is going to go on here for free soon.