It has begun! Android 4.1/Jelly Bean started rolling out to the European edition of the Samsung Galaxy S III this morning. The rollout began in Poland and should spread across the European landscape over the next few days/weeks. Of course this update brings a number of significant improvements, like Google Now and a faster and smoother UI, amongst many others. There is no indication as to win this update will come to the North American side of the pond, but it shouldn't be too long. We will keep you apprised.
Source: S3Forums via UnWiredView