Preview at WWDC likely in June, followed by September launch.
Siri Reportedly Coming to iPad with iOS 6
Mockup of Siri for iPad
Siri on the iPad is activated by a quick hold of the home button, just like on the iPhone 4S. The interface slides up from below the display with a clever animation. Siri is built into the iPad as a small window on top of whatever interface the user is currently interacting with. This Siri window with rounded corners sits at the bottom center of the display, as you can see in our mockup above. The Siri iPad interface takes very little space over the iPad interface currently in use, and is designed with the same linen texture as on the iPhone 4S. Siri for iPad also works from the lock screen.The report speculates that Siri for iPad may be exclusive to the new third-generation models, and it is unclear whether Apple will tout the feature at next week's Worldwide Developers Conference or if it will elect to keep it under wraps until closer to the public launch of the software later this year.