Google Now is a competitor to Apple’s Siri and one of the interesting feature which made debut with Android 4.1 Jelly Bean.If you want to get Google Now to your ICS device then all thanks to XDA member.
How to install Google Now on your Android 4.0 ICS running device
To install Google Now you need a rooted Android device running a ICS AOSP rom.
1. Download Google Now file to your computer http://goo.im/devs/chris41g/GoogleNowICS.zip.
2. Transfer .zip file of Google Now to the SD card on your device.
3. Turn off your device and enter into Recovery Mode.
4. Now, select “install zip from sdcard” and then select the option “choose zip from sdcard”.
5. Choose .zip file of Google Now and then confirm to install by by tapping “Yes”.
6. When the process of installation is done select “Go Back” and then select “reboot system now” to reboot your Android device.
You will now be able to use Google Now on your Android ICS running device.