Exactly when will the GS3 be updated to Jelly Bean? + Google Now

I know the build is finished but the carriers don't even have it yet. . . . so ummm WTF. - Not only that I wonder how Samsung will handle Google Now Vs their S Voice. I have a pretty good idea however.

If you own a S3 and want the stock home sreen on it you could always download Widget Locker which is Google Now ready.