iTunes 9.2.1 provides a number of important bug fixes, including:

• Disables older versions of some incompatible third-party plug-ins 
• Addresses minor issues with dragging and dropping items 
• Addresses a performance issue when first syncing to some devices with iTunes 9.2 
• Addresses an issue upgrading to iOS 4 on an iPhone or iPod touch with encrypted back-ups 
• Addresses other issues that improve stability and performance

iTunes 9.2 comes with several new features and improvements, including:

• Sync with iPhone 4 to enjoy your favorite music, movies, TV shows, books and more on-the-go

• Sync and read books with iPhone or iPod touch with iOS 4 and iBooks 1.1

• Organize and sync PDF documents as books. Read PDFs with iBooks 1.1 on iPad and any iPhone or iPod touch with iOS 4

• Organize your apps on your iOS 4 home screens into folders using iTunes

• Faster back-ups while syncing an iPhone or iPod touch with iOS 4

• Album artwork improvements make artwork appear more quickly when exploring your library

For information on the security content of this update, please visit:http://support.apple.com/kb/HT1222