Developer Ryan Petrich has successfully ported iOS personal Siri on an iPhone 3GS device. He took help from Steven Troughton-Smith and chpwn, the developers who previously ported Siri to the iPhone 4 and iPod Touch 4G.
Whenever there is a discussion or blog post on Siri port to other devices, iPhone 4 and iPod Touch 4G were considered but after this port 3GS is no longer a neglected device. It showed excellent performance while running Siri on it just like the iPhone 4S.
Another exciting thing about the Siri port on iPhone 3GS is that the developer has also integrated Activator jailbreak app with it. Activator integration is currently under testing. Rest of its communication with Apple servers to respond you is totally working fine.
Check out the video below to see Siri on iPhone 3GS:
Coming to its public release, well seems like they will not release it. The developer took help from Chpwn who previously ported Siri to iPhone 4 and iPod Touch 4G and then refused to release it to the public after showing a demo. They have also written a blog post to explain why its not possible for them to release it. In short, the port involves piracy and it would be illegal if they publicly distribute it.
Earlier we told you that Apple is also testing Siri for devices other than iPhone 4S. They have released special firmware with Siri installed in it to their employee for testing purposes. But they have showed no signs of releasing it because Siri is one of the exclusive feature of iPhone 4S and they would not like to effect sales of their new device.
If you want to install the GUI only version of Siri port to other devices you can follow the below link: