Google has officially announced that it is now rolling out Android 4.0.4 update for multiple devices. These devices include Nexus S, Galaxy Nexus HSPA+ and Motorola Xoom Wi-Fi. These updates are only available in select countries right now, like Xoom Wi-Fi is getting ICS in the US. Other device versions will get it on a later date.
Indian users will have to wait for the Android 4.0.4 update on their Nexus S smartphones. This update brings stability improvements, better camera performance, smoother screen rotation, improved phone number recognition and many more fixes.
Your device needs to be running on the stock build of Android 4.0.3 or Gingerbread (if you haven't received ICS update yet) to get this update. As the update is being released over-the-air, you will get a notification on your device to download and install it.