Just downloaded the eReader
software from the iTunes application store and am already reading a book from my bookshelf as I write this. Access to your bookshelf is easy, and book downloads are snappy (at least over wifi).
It's nice to finally have access to some of these older titles I purchased back in my early ebook reading days with my palm, as I don't do windows anymore and have gotten used to reading on the go with my Kindle.
Only downside (and I know it has been a constant gripe since the PeanutPress days) is the need to input credit card info to unlock the book even though I have logged into my account within the app already. Oh well.