Here you are some Italian publishers that I found who sell ebooks (very few, indeed):
www.guaraldi.it
www.edizionidellavigna.it (check their ebook forum, too:
www.elibri.biz/forum)
www.liguori.it
www.apogeonline.com
free resources:
http://www.liberliber.it/home/index.php
and Gutenberg Project, of course
