Screenshot
Then you'll be getting weather at a glance, using the voice-powered search a la Siri, and having the app speak answers to your questions back to you. When we tried the Android version last July, it blew Siri out of the water.
It's a free download and it's available right here.
If you already have Google's app, all you have to do is update to get the new functionality.
Now for an odd twist: Most Android phones can't run Google Now. The iPhone can.