This was, sadly, only brought to my attention this morning, but Tor has put up for download 24 books in DRM-Free digital form. The reason it's sad? You've got 'til tomorrow to download them.
The haul includes "Old Man’s War" by John Scalzi, recently reviewed here. I can also recommend "Mistborn" by Brandon Sanderson, the man tapped to finish out Robert Jordan's "Wheel of Time" series.
I'm sure there are many more books here worth reading - go get them while you can!
Free Digital TOR Books
Tor is also offering new short stories by some name authors. Stross's story is set in his "Laundry" universe, while Scalzi's develops the 'verse created for Old Man's War.
This is nice, but I've downloaded most of these already. I signed up on the Tor email list, and about once every week or two I get an email with a new book to download.