iPhone developer Steven Troughton-Smith has been working on porting the iPhone 4S’ Siri personal assistant application to other Apple devices for a couple of weeks now, and the popular new feature can now be run successfully on the iPhone 4 and iPod Touch.

“On the iPhone 4S launch date just a couple of weeks ago, developer Steven Troughton-Smith successfully ported the Siri user-interface and some of the underlying code from the iPhone 4S onto the iPhone 4,” writes Mark Gurman for 9to5Mac. “The port was functional except for the most important part: talking to Apple’s servers. Now, Troughton-Smith has followed up with Chpwn to get the server fully working on an iPhone 4 and iPod touch.”

Siri uses state-of-the-art voice-recognition technology and allows iPhone owners to perform a wide range of functions by simply speaking into their device. It’s certainly one of the highlights in the recently-released iOS 5’s 200-plus new features.

“At this point it’s all about confirming this works across devices, making it reproducible (we got it working on two devices today), and documenting everything,” Troughton-Smith told Gurman. “It does require files from an iPhone 4S which aren’t ours to distribute, and it also requires a validation token from the iPhone 4S that has to be pulled live from a jailbroken iPhone 4S, and it’s about a 20-step process right now.”