Visit Project Gutenberg (www.gutenberg.org). This site contains more than 20,000 books with expired copyrights that are now in the public domain. Visitors can search by author, title and subject as well as see which titles are the most popular with other visitors.
Visit Google Books (books.google.com), which has the text of 7 million books. You cannot download all of those books for free, but you can search them. So if you are looking for a recipe, wine review, crochet pattern or any other topic, you have a good chance of finding it here. Also, like Project Gutenburg, the site also features several books now in public domain that can be downloaded in their entirety for free.
Visit Amazon (amazon.com) and Barnes and Noble (bn.com). While both sites charge a fee for the majority of their e-books, both also carry a large selection of titles that site visitors can download for free, too.
Visit your public library. Many public libraries purchase several digital copies of new books, which patrons check out the same as a physical book. They can then read it on their computer or e-reader. Ask at your local library or try its website to see if it offers this service. E-books offered through your library will not be limited to those in the public domain; patrons should be able to find best sellers as well as classics.
Visit Wyvern's Library (see link in Resources section) and other similar websites if you are a fan of the science fiction and fantasy genres. Many of these sites will offer a large assortment of both professional and amateur authors' works.
Visit Many Books (see link in Resources). This site is a diverse assortment of e-books. Visitors can search by title, author and genre. The site also makes it easy for users to access new titles added to the site.