iBooks Can Now Open EPUB Files Directly
Adam Engst at TidBITS details an important change in how iBooks handles .EPUB files opened directly on iOS:
The practical upshot of this fix is that you can now transfer EPUB files into iBooks far more easily than before, when the only way was to drop them into iTunes and do a USB sync. For individual users, that means you can send yourself an EPUB via email and transfer the attachment to iBooks, and you can also copy EPUB files into Dropbox and use the iOS Dropbox app to send them to iBooks.
From our perspective as a publisher, even more important is that you can now tap a link to a .epub file in Safari and use the Open In interface to open the file in iBooks.
Basically, forwarding books bought / downloaded in Mobile Safari to iBooks got a lot easier thanks to the "Open In..." menu. Project Gutenberg books work great with this method.