Meet Evi, not Siri but what they both do is fairly similar according to the developer. When the iPhone 4S was announced a lot were disappointed expecting a phone that will entirely look different, the phone looked the same but it had Siri which no other phone had. There were attempts to hack the system to bring it to older devices but that was not entirely successful.
Anyway, Evi is just about the same, it is an artificial intelligence in form of an app where you can either type to ask or just speak up and “she” will answer your questions and obey your commands. It is very much like how Siri functions and that is just judging by the video itself.
I do not think it is as robust as Siri is but it is a welcome addition to the App Store. I might give it a try sometime.
Download iPhone App ($0.99)