Google’s Google Now is perhaps making as much noise as the Jelly Bean update that it is part of. What this means is that you need to have Jelly Bean on your device first to have a taste of Google Now. However, that is the ideal case and there always are ways to get around such scenarios. As the folks at XDA Developers forum have hit upon, having Google Now up and running on your device is perfectly possible even if it is not running the latest Android version. However as a pre-requisite, you need to root the device and install some codes which makes it possible to have Google’s take on personal assistance on a mobile device even if it is running Ice Cream Sandwich.
To be more precise, the requirements to have on board Google Now include an ARMv7 device, it should be rooted, and should be running ClockWorkMod Recovery and have Ice Cream Sandwich.
Head over to the XDA site for more on this.