It's been ten days since Siri hit the scene and the virtual assistant is in the process of being torn apart by the hacking community. Siri, as it exists on the iPhone 4S, has been ported to the iPhone 4 and now the iPad 1. Developer Steven Troughton-Smith, who worked on the iPhone 4 port, has shared his progress with @jackoplane who has successfully ported the app to the iPad 1. Several images of Siri running on the tablet device document this achievement.
Unfortunately, neither the iPhone 4 nor the iPad port is fully functional at this point. Siri still needs to connect to Apple's servers to work