There are news few hours ago that Apple iPad mini event will be streamed only on Apple TV live from San Jose. But according to the recent updates on their website, ANY Apple product owner can stream the event online.
Live streaming video requires Safari 4 or later on Mac OS X v10.6 or later; Safari on iOS 4.2 or later. Streaming via Apple TV requires second- or third-generation Apple TV with software 5.0.2 or later.

Here’s the link