If you use anything other than Calibre for the Mac to organize, share, convert, and even read your digital books, check out the web site and seriously consider taking the plunge and trying Calibre for free … in fact, other than a donation, you can use Calibre without providing the developers any monetary compensation (although how could you live with the shame).
Also note that Calibre interfaces with iTunes and provides a path to transfer (and convert if necessary) any books from the internet into iTunes and, of course, then onto your iPad or iPod. Having accumulated a large library of eBooks in PDB format for the old Palm (Pilot), I found it very convenient to transfer the old files into this application which automatically performs the required file conversions before sending them on to other devices. It’s not perfect but it is the Swiss Army Knife of eBooks. Who knows, with the help of Calibre you just might learn to enjoy the convenience of digital books … I am finding them more and more appealing and the extra space on my bookshelves now leaves me room for my collection of vintage dust bunnies.