Apple is letting customers try out one feature of its upcoming iCloud months before the service is set to debut.

Late Monday, Apple made a beta of iTunes 10.3 available for downloading, and switched on "iTunes in the Cloud" for that application as well as for the iTunes apps bundled with iOS 4.3.3, the current version that powers the iPhone, iPad and iPod Touch.

iTunes in the Cloud is Apple's name for the iCloud feature that lets users download tracks and albums purchased through the iTunes store to as many as 10 different devices, including Macs and Windows PCs running iTunes 10.3, iPhones, iPads and iPod Touches.

Once downloaded to a device, any of those tunes can be played.

Apple CEO Steve Jobs unveiled iCloud Monday at the Worldwide Developers Conference (WWDC) keynote, and said that the full service would be available this fall, at the same time that iOS 5 launches.

In iTunes 10.3, users must set a new preference option to automatically receive music purchased on other devices linked to the same iTunes account. That setting is under "Store" in the iTunes Preferences window; checking '"Music" under the "Automatic Downloads" section, for example, auto-downloads tracks bought on, say, an iPhone, to the Mac or PC running iTunes 10.3.

On an iPhone, the same option is under "Store" in the "Settings" app.

Alternately, users can manually request downloads to each device.

On an iTunes 10.3-equipped Mac, for instance, users can select tracks to download from the Purchased section of their library, clicking on the cloud-style icon to begin the download.

The process is similar on an iOS device.

Apps and books purchased through Apple's iBook app or via iTunes can also be downloaded to multiple devices.

The for-a-fee "iTunes Match" is not yet available, however. That $25-per-year service will scan a customer's iTunes collection, match those tunes that were not bought through Apple's store against the 18 million tracks in Apple's library, then make the matches available for instant downloading to the maximum 10 devices.

The beta of iTunes 10.3 can be downloaded from Apple's Web site.