Originally Posted by BookCat
Is it a Sony format that you're starting with, or that you want? If the latter, and you're working in text, simply use a Word processor. Design a template based on the size of the screen of your Sony; paste in the text; then change the font size to 18pt. Under "file" find "properties" and enter the book's name and author (to show up on the reader), then save as RTF.
God, no, don't use RTF. It doesn't support hyperlinks, or a table of contents, or pictures, and has very large files. RTF was never intended to be anything else than an "interchange" file format, and that's still what it's best for.
It's very little additional work to produce a "real" eBook.