Looks like Siri is Down today for iPhone 4S users in the United States. As of right now we are unaware if and when Siri functionality will return for iPhone 4S users. If Siri is down for you right now, feel free to post below where you are located and how long you have been without service. This information will help other users identify whether it is a problem at Apple or just with their iPhone 4S.
Right now all Siri will do is say she cannot complete any requests. This is not an official status from Apple just an observation.