Apple iBooks 1.1.1 Update Catches Up with Kindle App's Audio/Video eBook Capability

Apple updated its iPhone/iPad ebook reader and added a bunch of new features:
iBooks 1.1.1
– Double tap an image to view it in more detail
– Performance improvement when reading PDF documents
But, I think the update is mostly to catch up with the recently released Amazon Kindle iPhone/iPad app update. Kindle for the iPhone and iPad gained the ability to present audio and video material associated with books. I wrote about the updated Kindle app late last month:
Amazon Re-inventing Ebooks & Starting the Revolution on the iPad & iPhone
iBooks 1.1.1 provides the ability to present audio and video material integrated in an ebook too. Amazon’s collection of audio/video ebooks has grown substantially since last month. Most of the ebooks are music books. But, I expect to see other categories of books take advantage of this format soon.