A developer at the XDA-Developers forum has posted a custom build of Ice Cream Sandwich for Google Nexus S. And he has luckily got almost everything working except for a few features.
Google unveiled their new Ice Cream Sandwich at a special event in partnership with Samsung. And the code got open-sourced recently and a developer has successfully made a custom build of ICS 4.0 and have ported it onto Nexus S i9020t. Remember, the Nexus S haven’t got an update from Google yet.
kwiboo has made this build and has shared it for testing. The developer has tested it on Nexus S and have got some features (many features intact) working successfully. The build works on both Nexus S and Nexus S 4G currently. Before you can update to this build, remember that this is still a AOSP build and not all the features are working on the device.
There are some bugs still. Such as the USB mass storage and you need to add your WiFi connection manually in order to get it working. And you also need to add a lot of drivers manually onto the device to get some features working normally.
Reading throughout the thread, I can say that the build is considerably stable and the support from other developers have been tremendous. So if you are going to try it on your device, feel free to post your problems in this thread. If you are ready and want to get your Nexus to run Ice Cream Sandwich, just download the source from below.[add_button colour="green" position="Full width" link="http://forum.xda-developers.com/showthread.php?t=1354263"]Download Ice Cream Sandwich for Nexus S and Nexus S 4G[/add_button]