Famed jailbreak developer Ryan Petrich has released a video of Siri running on the iPhone 3GS. Petrich is most known in the jailbreak community for his Activator extension that brings customized gestures for specific apps and tweaks in iOS.
In the above video, Petrich is demonstrating Siri on an iPhone 3GS. He has also mentioned that he is working on Activator integration with Siri.
This hack comes courtesy of developer Steven-Troughton Smith and chpwn, who recently demonstrated Siri running on the iPhone 4 as well. The Siri port cannot be released at this time due to the illegal nature of the hackery, and the fact that it would take both piracy and an iPhone 4S jailbreak to release.
More to come as this story unfolds.