http://www.saberingles.com.ar/bookstore/librosgratis.html

 
In this link  you can find a lot of english books from different authors. 

To download a book you have to follow the next steps:

1. Clic in the link 

2. Choose a book from the page (In the left side you have the authors' name and in the right side you have the name of the books).

3. When you have chosen the book, clic in the name of the book.

4. When the book is downloaded, you have to clic in the downloaded book.

5. After that you have to clic in the selected folder:

Then the book will appear automatically selected in "winrar" format:

6. In the book you have to clic with the right bottom and then clic in the option "extract in the specified folder" (you can do a new folder in your desk to save your english books) and then clic in accept. 

7. After all this steps you have to go to your folder in wich you have saved your book, open it and start to read!