Hey everyone jones'n for JB! As described previously, follow the directions of this link and you will have JB. Did it on my wife's S3 last night and my son's tonight. First try. No rooting or the such. Works like a charm. Merely fools the Sprint servers into thinking your phone is next in line for the update.
Sprint Community: How to Force OTA Update of Jelly Bean 4.1.1 on Samsung Galaxy S3 without doing all the programming nonsense
Sprint Community: How to Force OTA Update of Jelly Bean 4.1.1 on Samsung Galaxy S3 without doing all the programming nonsense