I've heard many mentions of Google Now over the last few weeks, not sure why, it's been around for a while now, but anyway I was curious to find out more.
First problem is "what is Google Now?". Well it's not really an application, more of a feature of the Google app in Android (I'm not an iOS user at the moment).
The larger issue happens if you're a Google Apps For Business as I am, then it's surprisingly difficult to enable at all. The whole process is documented nicely here:
1) Launch your Google Apps control panel by going to http://google.com/a/<your custom domain>.
2) Click Organization & Users.
3) Click Services.
4) Scroll all the way down until you reach Google+.
5) Click on the Configure premium features link.
6) In the left pane select Mobile.
7) Scroll all the way down to Android settings.
8) Check the boxes for Enable Google Now and the optional Enable Lock Screen Widgets.
9) Do not forget to hit Save.
Now you can enable Google Now inside the search application on your phone or tablet. Out of the box it displays little, but very quickly you start to see 'cards' which are gathered from various sources; your GMail, calendar, and search history. So because I am travelling to St Louis this weekend I can already see a card which is tracking my first flight...
Initial impressions are rather good. Because I use Google services a lot it should be able to see everything I need. But if you're not as heavily invested in Google as me then your milage may vary.