I shall look into it some more. I'm of the old school and only starting to get out of paper
I have an e-book I purchased last year, and it reads almost all file types, so I haven't really paid much attention to who supports what format. and it leaves things pretty open to finding people uploading books all over the place on the net.
I have a Kindle on my Blackberry Playbook (only just remembered...) so it might be usefull for this