Wired reports on efforts by publishers to ready their content for publishing in e-Book format, on multiple devices and platforms, but with the iPhone featuring highly among them.
There are a growing number of eBook reading applications available for the iPhone (despite Steve Jobs claiming that "people don't read anymore") and I have covered a number of them in this blog.
Also, it seems that many individual books are being released as standalone "self-reading" applications on the App Store.
I can only think that this is an easy way for publishers to do the eCommerce for each book, and have the browse and purchase experience tightly integrated into the iPhone experience, as well as being a way to surreptitiously make the "App Store" a "Book Store" by making "Book" = "App".
I don't have numbers on the size of the application-book combination download versus the book content alone, but it must be much bigger as the book content itself can be as small as a few hundred KBytes without images. Thus they will start to fill up your iPhone/iPod memory more quickly.
Is that an issue? What happens when you delete a book (App) you've read? Can you get it back for no charge later?
I assume you cannot read the same book content on your PC/Mac where iTunes is running?
Don't expect much in the way of integration across publishers, or the ability to look-up a word in a dictionary/thesaurus from one publisher while reading a book from another.
One positive aspect is that there shouldn't be any format concerns (a Book can always read itself as it is the reader!), and you will always have a compatible and up-to-date reader software for each book you buy.
Having books sold via the App Store or iTunes will enable Apple to neatly track sales and decide whether they want to do something about it or not, such as providing explicit support for eBooks in the iTunes store, in the iPhone "Apps" store and in the iPhone/iPod itself.
Providing they don't restrict purchase and downloads to Wi-Fi only (like they do for music) then they could provide a great browse and purchase experience similar to that of the Amazon Kindle (only faster, being 3G, and in color), providing a more mobile (but limited in screen size and outdoor readability) reading experience.