Although hackers around the world have been successful in porting Siri to iPhone 4, iPhone 3GS, iPod Touch 4G and even iPads, and as some reports came in claiming that Apple is considering porting Siri for iPhone 4, all rumors have been quashed after an engineer at Apple posted “Siri only works on iPhone 4S and we currently have no plans to support older devices”. So its an end to a discussion of putting Siri on older devices (atleast legally).
You can always use Siri on your older iDevices at the expense of losing warranty. Do you like Apple’s move on this thing? Let us know.