If you have an electronic reader—Kindle, Nook, etc.—or one of the reader apps for your PC, Mac, smart phone, or tablet, then there are a ton of free books out there. Enough books that no matter how fast you read, you couldn't read all of them in a single lifetime.
I hope that by now you know about the availability of all the “classics” from Project Gutenberg, The Internet Archive, and Google Books. These sites offer “bare bones” versions of the books. Project Gutenberg focuses on plain text versions with very little formatting, while the other two sites primarily offer scanned PDF versions with OCR conversion to text. While these sites now offer one or more versions designed for electronic readers, the disadvantage is that the files have been produced by automation directly from the OCR conversions.
A much better source for classic texts is MobileRead, an “online community where e-book newbies and industry veterans alike interact and share their experience with e-books and e-book technologies.” There, the E-Book Library contains versions that have been carefully created by volunteers. For the most part, the editing and formatting are exquisite. Most of the books found at MobileRead are more finely crafted than those that come from any Publisher.
But what if you want to read more than just the classics? What if you want to read books that are not yet in the public domain? What if you want to read recently published books? Yes! You can get some of those for free, too.
If you read science fiction and fantasy, check out the free books in Baen's Free Library. Most of the books found here are the first one in a series. What a great way to find out if you like the author or the series! And, of course, they sell electronic books via their WebScription Ebooks site.
A number of authors now give away some of their books. These range from new authors just wanting to get a book “out there”, independent authors, and even established authors like Cory Doctorow and Charles Stross. These authors have several outlets—their own web sites, Smashwords, and Feedbooks—to name a few.
And publishers have realized that offering the occasional free book can spur further sales. I've become a regular follower of Books on the Knob, a blog that lists free and deeply discounted eBooks from all the major sources. There are other places online to find out about free books; a Google search turned up over 36 million hits!
So, if someone gave you one of these electronic readers for Christmas, get out there and fill it up with lots of books to read!