Jelly Bean is now available for Sony Xperia T. The Android 4.1.2 OS, that toppled the Ice Cream sandwich, has a better UI, enhanced camera application, Google Now as your PA, automatic widget re-sizing and other new exciting features. The version number is 9.1.A.0.489.
It is still not clear the regions in which jelly bean is available. But Xperiablog states that it is available in Netherlands at least. Get more information here.