Today I noticed on our iPad here that the iBooks application had a pending update. A quick look at the change log revilved the following:

What’s New in Version 1.1

• In addition to iPad, iBooks is now available on any iPhone or iPod with iOS 4.
• Open and read PDF documents from Mail. PDF documents will be added to your library and appear on the PDF bookshelf. You can even search PDFs for words or phrases and bookmark your favorite pages.
• Take advantage of new ways to bookmark. In addition to highlighting a word or a passage, you can now also add notes or bookmark an entire page with the new page ribbon.
• Keep your bookmarks, notes, and your current page wirelessly in sync between iPhone, iPad, and iPod touch with the new automatic bookmark syncing feature.
• See your book pages in a new font, called Georgia.
• Read your books on white or sepia colored pages.
• Choose left or fully justified text layout from Settings.
• Read pages with greater ease by increasing to even larger font sizes.
• Enjoy greater stability and better performance. (Source iBooks in the iTunes Store)

We personally hadn’texpereinced any stability issues with the first version, but then again we didn’t use it all that much, since it didn’t appear to have PDF support (For PDFs we have been using Stanza, which has also been updated with OS4 support).

Let us know in the comments how your find iBooks and if you are trying it out on an OS4 device.