Chpwn and Ryan Petrich have released “Spire”, a jailbreak tweak for installing Siri on unsupported hardware (basically any iDevice that isn’t an iPhone 4S). Rumors of this awesome app have been swirling around for a few weeks, and it is now available through Cydia for free. Spire works on the iPhone 3GS/4, iPod Touch 3/4, and the original iPad, but note that the mic on the Touch isn’t quite up to par with the iPhone, so you may have to annunciate more than usual for accurate results.
Since the tweak uses legal methods of connecting to Apple’s servers, you’ll need to use a proxy server to insert info from an iPhone 4S. A easy way to set up your own proxy may crop up over the next few days, but for now, you’ll have to create your own.
Spire uses a new method to obtain the files necessary for Siri, so it doesn’t have the copyright issues encountered by previous attempts. Similarly, rather than directing all traffic through a specific proxy server (and the associated privacy issues), Spire allows you to specify your own proxy server.