In this post, I demonstrate how to overlay text over your illustration/page in Gimp. After you complete all your pages, save them out as a JPEG and PDF files. For simple consolidation use the pdfs and drag and drop the thumbnail of one over the other starting with your book cover. For Ereader files (.epub files) you can build your book page by page in a google document and then download it for free as a .epub file. At that point you're ready to sell it or post it online! Go ahead and make yourself famous!