SiriPort (Original) is a Cydia tweak for iPhone 4, iPhone 3GS on iOS 5.1.1, which allows you to run Siri on iOS 5.1.1. This is like we mentioned before, the Spire and Spite. SiriPort (Original) 5.1.1-3 works on non-iPhone 4S device without setting a proxy server or an iPhone 4S in hand.
To install SiriPort (Original) on your iOS device. Obviously, you have to make sure that your device has been jailbroken on 5.1.1. The jailbreak steps using Absinthe 2.0 are very simple, clicking here to download Absinthe 2.0.4. Once your device be jailbroken, you need to add this repository in Cydia:
http://repo.siriport.ru
Then install a package SiriPort (Original) 5.1.1-3 likes to install a common tweak. Back to the home screen and browse this link to install the certificate:
http://siriport.ru/siriport_ru_original.pem
Reboot your iOS device, at this time you can activate Siri and say “Hi Siri” Siri won’t work, wait 20 minutes and try again. (Say “Hi Siri”)
If Siri does not work [No respond] Repeat the above step until Siri is activated
Note: SirPort is used by a lot of people and if you are not having any luck getting a response from Siri it could simply be because the SiriPort servers are overloaded.

Never connected and after removing caused boot logo loop, had to restore.
it worked for me on 5.0.1 install siri on ipad 1 and iphone 3 cdma.
sorry i messed up i meant to say i installed it on an ipad 1 and iphone 4 cdma. lol