Get Siri On Your iPhone 4, 3GS or iPad With i4Siri
You are already probably familiar with the i4Siri project; at the end of last year we told you to keep your fingers crossed for a port if Siri is the only reason you’d consider purchasing an iPhone 4S (despite the improved camera and processor). If you’re rocking an Apple iPad and want to use Siri, this might be a good chance to consider it, since Apple failed to bring the personal assistant to the New iPad (and iOS 5.1).
In order to get it up and running you will first need to jailbreak your device (regardless if you’re on an A4 or A5 device, regardless if you are running iOS 5.0.1 or iOS 5.1). If you already have that, just follow the source link down below to get step-by-step installation instructions.