Google has started rolling out Android 4.1.2 over-the-air update for Galaxy Nexus, Nexus S smartphones and Xoom Wi-Fi variant tablet (only in US).
The update brings performance and stability improvements apart from other small changes. The update for Galaxy Nexus and Nexus S does not include the landscape launcher support, which was present in the Nexus 7 update, but you can expand a notification with a single finger.
As the update roll-out is gradual, don’t worry if you don’t the update notification right-away. You can also go to Settings<<About Phone/tablet<<Software Update to manually check for the update.
Google had earlier released the same update for Nexus 7 tablet and it has already uploaded the factory images for all the devices at its developer website.

I got it yesterday afternoon on my Galaxy Nexus, here in India 🙂
i dont get update setting