iTunes 10.5 comes with support for iCloud.

A day ahead of Apple's big release for iOS 5, the new version of iTunes lays the groundwork for the desktop hooks to the next version of the mobile operating system. The big new feature in iTunes 10.5, which you can download for Windows and Mac, is support for iCloud, Apple's service for syncing data wirelessly.

The iCloud change is significant. The free service enables you to store music and video purchases in Apple's cloud service, and make them available across your iOS devices or computers with iTunes installed. Automatic downloads are also supported in this version, which means that when you buy music through the iTunes Store, you can automatically download a copy to any of your other devices or computers. Previous purchases are finally downloadable without any additional cost, as long as they're still available in the iTunes Store.

The new Wi-Fi-syncing feature enables you to sync devices connected to the same Wi-Fi network. Apple has released a troubleshooting guide for people who encounter difficulties setting it up.

One feature that was active in the iTunes 10.5 beta, the iTunes Match service, has been disabled for now. The service, costing $24.99 per year, lets iTunes "match" a person's music library to the music database offered through Apple's iTunes Store, then make those tracks available to any iCloud-enabled device or computer. This includes songs you didn't purchase through Apple. Although a firm activation date has not yet been announced by Apple, iTunes Match is expected to launch at the end of October.

Windows users will find that iTunes has been permanently unbundled from QuickTime updates, making for a slightly faster download experience.