Google has announced Google Now, the Jelly Bean's Siri competitor. It is a new feature introduced in Google’s mobile operating system, Android 4.1 (aka Jelly Bean).
Google Now, is a smart personal search assistant that allows you to easily track flights, keep an eye on traffic and your calendar, check sports scores and weather, see suggested places nearby, and more. The service also offers "Google Now Cards" that automatically populate based on your searches.
Google Now can be accessed on any device running on Android 4.1, by swiping up from the bottom of the homescreen. It is already been referred to as a “Siri killer” by some Android fans because of its ability to not just assist you, but to proactively alert you to new information based on your needs.
You can check out the Google Now webpage and this article on Techcrunch for more info. This hands-on with Google Now at TheVerge.com is quite informative.