How To: Get Siri UI on the iPhone 4 or iPod Touch 4

Step 1: Jailbreak your iPhone/iPod Touch on iOS 5 using Redsn0w or Sn0wbreeze.
Step 2: Download files required for the Siri port to iPhone 4 and iPod touch 4G. (You will have to find these files yourself as we wont be able to share these files with you)
Step 2: Download files required for the Siri port to iPhone 4 and iPod touch 4G. (You will have to find these files yourself as we wont be able to share these files with you)
Step 3: Using a file explorer for your iOS device, copy over the AssistantServices.framework folder you downloaded in Step 2 to Root > System > Library > PrivateFrameworks after plugging in your device to your computer via USB.
Step 4: Transfer all files from the Springboard folder in Step 2 to Root > System > Library > CoreServices > Springboard.app on your iOS device.
Step 5: Using iFile (you can get it from Cydia), open the .plist file for your iOS device from System > Library > CoreServices > Springboard.app. It will be named N81AP for iPod touch 4G and N9x for iPhone 4 (where x may be 0, 1, 2).
Step 6: Add a new property list named assistant to the .plist file and set its class as Booleanwhile setting its value as YES.
Step 7: Add the following to the .plist file: assistant
Step 8: Respring your iOS device.
There you go!