Right now Siri si working for everyone!
A really short It started around 5 PM (GMT +1) when Siri stopped working on iOS devices.
In fact, when you try do ask something, the device will remain stuck for some minutes and then report that it can’t accept any requests at this time.
Probably servers are down due to an overload, because today’s when the iPhone 5 got released i many countries and users wanted to test the new iOS 6. When Siri will be available again, we’ll let you know as soon as possible.