Google phones are known to get Android update before any carrier variant android device. This has been the case for the Google Nexus S as it was one of the first Google devices to receive the latest Android 4.1 Jelly Bean update. Today Google released the update build for the global Nexus S (Soja) and the Nexus S 4G (Sojas). The new firmware update for the Google Nexus S is JRO03L and JRO03R for the Nexus S 4G.
As this is a flash ROM, if you are not used to flashing your phone we do NOT recommend you to try this. This is only for the international versions of the Nexus S and the Nexus S 4G ,excluding Korean Models. Guess the rest have to wait for it as usual.