Following the footsteps of the Google Nexus 7, the Samsung Galaxy Nexus and Nexus S got their own treatment of Android 4.1.2 Jelly Bean. The 15.1MB update is currently seeding to GSM/HSPA versions of both smartphones over the air.
The update is a minor improvement over its predecessor. It includes the usual performance and stability fixes. Landscape mode however, will remain reserved for the Google Nexus 7.