Apple has released iTunes 9.2 beta for registered iPhone developers. iPhone 4 and iOS 4 both require iTunes 9.2. It is currently available for Mac OS X only.
iTunes 9.2 features include:
Sync with iPhone 4.
Sync and read books with iPhone or iPod touch with iPhone OS 4 (iOS 4) and iBooks 1.1.
Organize and Sync PDF documents as books. Another feature in iBooks 1.1.
Organizing apps in Folders. A feature of iOS 4.
Faster back-ups while syncing iOS 4 devices.
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