First time accepted submitter jisom writes with something that will probably not be working come morning. Quoting the source: "Today, we managed to crack open Siri's protocol. As a result, we are able to use Siri's recognition engine from any device. Yes, that means anyone could now write an Android app that uses the real Siri! Or use Siri on an iPad! And we're going to share this know-how with you."
Basically, Siri sends the data to the processing server using non-standard HTTP extensions. Of note is that the audio is encoded using Ogg Speex