Siri, the personal assistant extraordinaire, is one of the hallmark features of the iPhone 4S. But why oh why can she not be on the iPhone 4? She is, after all, just software. iPhone developer Steven Troughton-Smith thought the same thing and actually ported Siri over to the iPhone 4.
His first effort was less polished than the one above but this latest one (in the video above), shows Siri working just as buttery and delicious on the old iPhone 4 as on the 4S. It loads just fine, you see the complete Siri interface, actions and she can completely understand you but you can't do anything with Siri on the iPhone 4 yet. Apple isn't authenticating Siri commands from an iPhone 4 on its servers so all you get to stare at is the purple and silver.
Hopefully, Apple will introduce Siri to more devices because the software is amazing. They don't have an excuse anymore, hardware-wise the iPhone 4 can clearly handle it.