Alongside the first beta of iOS 5, and another developer preview of OS X Lion, Apple has released iTunes 10.5 beta, which is required to sync iOS 5 devices (and enable more iCloud-related features), as well as the developer beta of their new iCloud service.
The iTunes 10.5 changelog confirms that the new iTunes beta build enables compatibility with iOS 5 devices, and also brings some minor graphical updates that resemble Lion’s changes to the system toolbar and buttons. Also, a new preference panel within Settings lets you enable Automatic Downloads for iOS devices.
The iCloud beta, accessible through the Dev Center, includes all the instructions needed to get iCloud working on iOS devices, Macs, and iPhoto, and includes a download link for iPhoto 9l2, so you can test in in a separate environment without tampering with your existing photo library (useful for testing the new Photo Stream features.
Obviously, many of these features are exclusive to Lion and Apple clearly tells developers to go download the OS X Developer Preview if they want to test iCloud’s functionalities.
Some cautions on the iPhoto update from MacStories:
The iPhoto update will replace your current version of iPhoto. Your existing iPhoto Library will NOT open with this version of iPhoto. For this reason it is recommended that you work on a test/development system ONLY when using this release. You will not be able to revert the system to an earlier version of iPhoto without doing a clean install of Mac OS X and reinstalling iPhoto either from your original installation DVD or by downloading from the Mac App Store.
An iCloud Control Panel for Windows is also available to enable “Photo Stream, Contacts, and Calendar” on a PC through iCloud.
