While Google Now has only been available for Jelly Bean devices (officially), that hasn’t stopped people from finding numerous ways to get it onto their Ice Cream Sandwich devices. Google Now has been available for Ice Cream Sandwich devices for some time now thanks to the folks at XDA. Back then you just needed to have a rooted device and being able to sideload an .apk file and changing some things in your build.prop.
Now there’s a newer method that utilizes an application called GNow Handlebars. Your ICS device still has to be rooted, and all you have to do is install the application and follow the simple steps:
1. Open app
2. Make a choice
a. Install (Install Google Now)
– choose apk
– rename voicesearch.apk to voicesearch.apk.bak
b. Restore (Restore Google Search)
– rename voicesearch.apk.bak to voicesearch.apk
Give it a shot and let us know if it works flawlessly for you. Download links are also provided in the source links below!
source: XDA Developers