Revealed last week with a leaked screenshot from iTunes and officially announced earlier today at the WWDC keynote, the “Automatic Downloads” feature for iOS device is now live and accessible from the Store menu inside the Settings app on an iPhone, iPod touch or iPad running iOS 4.3. Here’s how it works: once enabled in the Store menu, the new functionality will allow you to beam apps, books and songs across devices – Macs, iPhones and iPads. For a first test, I enabled the menu on my iPhone, and started downloading a free app on my Mac. Within the seconds, the download started on my iPhone, which wasn’t connected via USB – it was an OTA download based on the fact that I hit “download” on my MacBook Pro.

The iPad, which was not enabled to have Automatic Downloads, alerted me to say I had to activate the feature if I wanted to see purchases becoming available on it.

Once activated on the iPad too, I downloaded an app on my iPhone and it started downloading both on the iPhone and iPad, automatically. But what about updates, not new purchases or free downloads? The system seems to be a bit unstable now: I had three app updates on my Mac, and I downloaded them. Those updates were showing up on the iPad App Store app with a red badge, but the download didn’t start automatically as with a new purchase / download. However, as soon as I opened the App Store on my iPad, those updates were gone – as if the device downloaded them in the background without me seeing a loading indicator. Maybe Apple simply needs a better UI for app updates (again, not new purchases) or better integration with iTunes 10.2.2 on the desktop (the announced iTunes 10.3 is not available yet).

To test the new Automatic Downloads for iOS and Macs, go to the Store menu on your iPhone and iPad and turn the switches to “on”. You can also decide to use cellular data when not on WiFi.