There is no doubt that Samsung is leading Android Smartphone manufacture in this universe. The most best part of the world leading company, Samsung get outs the source code more quickly. For the Samsung Galaxy S3, the company has posted the new ICS source code on its Open Source Release Center. You can grab it for yourself here.
Release of the source code for Samsung Galaxy S3 will help Android developers to tailor their specific apps for the Galaxy S III, as well as allow ROM makers to go hog wild with the new hardware.
Please keep in mind that the source code available is for the international I9300 version (the only one that’s been released so far) so any modifications made may not carry over to LTE variants, or the American version Samsung Galaxy S3.
Moreover, the source code does not include the Samsung’s native apps such as TouchWiz interface and S-Voice are created separately as copyrighted software, and aren’t beholden to Android’s open source license. However there are already apps for S-Voice floating over internet and TouchWiz is already ported for Nexus.