Zita
Welcome to Mobileread ....
You will find a surprising number of books that are issued without DRM - Calibre has been mentioned as a converter (once DRM has been removed); but Calibre has a developing sister site advertising books that are DRM-free
http://drmfree.calibre-ebook.com/.
Places like Smashwords and Fictionwise also sell books that are DRM-free....See also links in my signature line to stores ....
Admittedly these links will, primarily, be for fiction books and probably not what you want .......
