Good news for those who have been waiting for a full working Siri port on iPhone 4 and iPod touch 4G. It's finally here, and you can install it now. All you need to have is a jailbroken device. Do keep in mind that the legality of this port remains to be decided.
This full Siri iPhone 4 and iPod touch 4G port has been developed by a relatively unknown team called CD Team. H1Siri, the name of this port, not only brings the full Siri GUI, but will also give you full functionality. Be advised that the team uses proxy servers which can potentially be used to grab data from your device. You will be responsible for anything that occurs after you install Siri port on iPhone 4 and iPod touch 4G.
Install Siri Port On iPhone 4 And iPod Touch 4G:
Step 1: Download iOS 5.0 or iOS 5.0.1 for iPhone 4 and iPod touch 4G
Step 2: Jailbreak your iPhone 4 and iPod touch 4G
Step 3: After the jailbreak, launch Cydia. Tap on Manage followed by Sources.
Step 4: Tap on Edit then Add, then add any one of the following repository in Cydia: http://iphone3gsystem.fr/cydia OR http://www.cydia.be
Step 5: After the repo has installed, search for H1Siri in Cydia and install it. Installation will take a lot of time as this package is of 109 MB. When installation finishes, reboot your device.
Step 6: When device has rebooted, Go to Settings.app and tap on General followed by Siri. Switch it on from there and you have successfully installed Siri port on iPhone 4 and iPod touch 4G.
Once again, we advise you to think twice before doing this, because your information is going through proxy servers. If you just want to try it out, clear all important data such as emails, contacts etc from your device before you install Siri port on iPhone 4 and iPod touch 4G.
It is possible that you might encounter network error. This is due to the fact that the proxy servers are getting hammered with traffic at the moment. You can wait it out if you face connection errors. The developers have said that they're shifting to servers that will be able to handle the load better.
If you face any issue, just leave a comment down below.
UPDATE: Add the following repository if you can't download H1Siri from the two repositories given above: http://www.cydia.iphonetweak.fr. Those who have already installed it and are getting connection error messages, keep in mind that the servers are getting hammered with traffic right now and it would probably take sometime before the CD Team transfers them to more reliable and load bearing servers.
Update 2: Here's another repository which now hosts H1Siri http://cydia.myrepospace.com/H1Siri. If you absolutely can not install it from any repository in Cydia, download the H1Siri.deb file from here. You'll have to manually SHSH the whole file in your device and then install it using iFile.