When Jelly Bean source was first released, it was automatically assumed that the first devices to receive an official update would be the Nexus devices. Not long after, that actually happened for the Galaxy Nexus and Nexus 7, leaving owners of older Nexus devices wondering when it would be their turn. In fact, the Samsung Nexus S forums had a thread dedicated to the countdown of the Jelly Bean update. Luckily, the wait is now over, as the Nexus S Jelly Bean OTA has been released.
The thread above, maintained by XDA Senior Member oldblue910, along with this thread posted by XDA Forum Member ffaiz.m both have download links to the OTA if you don’t feel like waiting for the OTA to get rolled out to you.
The OTA appears to only be for the i9020T and i9023. As reported by PocketNow:
According to reports, i9023 variants of the phone should be able to upgrade and there’s even a link for the file on Google’s servers. It also appears that i9020T flavors can also use the refresh.
Welcome to the official Jelly Bean club, Nexus S owners. For additional information, check out the links above._________