Since Apple unveiled Siri on the new iPhone 4S there have been users of older iPhone devices that are frothing at the mouth to get their hands on Siri code and bring the virtual assistant to other devices. That had been illegal since the files needed for the port were encrypted by Apple and using them was a copyright violation. With a recent iOS update; those files were left unencrypted. That raised the possibility of a legal port without hacking encryption.
A new installer has now surfaced that will install Siri on any jailbroken iOS device that you may be using. The installer is called the Spire installer. Spire goes around any copyright infringement and downloads about 100MB of files to get Siri working on your device. It uses a proxy server with information that comes from an iPhone 4S to act as a go between to get Siri to work since it needs access to Apple servers.
The Spire installer is on the Cydia store right now for you to try out. If you download Spire and install it on your device, be sure you let us know how well it works for you. I wonder whether Apple will be looking to kill this port, I would imagine it will be looking for that specific go between device to end the connection.