I found a way to force the OTA Update for Jelly Bean. Its actually quite simple, and it worked for me pretty quickly.
Step 1. Go into the settings menu on your phone and open the Application Manager. Now select the tab to see ALL of the applications
2. Look for "Google Services Framework" and click on it.
3. Press the Clear Data button, then click Force Stop, this will not hurt your phone or anything on it so dont worry! (If any of you are wondering about the Google Service Framework data clear, this is done because the Android update is sent out by Google, so when clearing the data and doing the force stop, it basically refreshes the current state and status of that service, which in turn makes your phone basically look for any updates.)
4. Now go back to the Setting Menu and go and to the System update area and go to Update Samsung Software. The date at the top where it says "Date last checked" should be something like 12/31/1969, which means your phone is now prioritized to recieve the OTA Jelly Bean update message.
5. Click the Check now button to check for the update again, your phone should recieve the update message. You might have to go back and repeat this process a few times, clearing the data and forcing stop, I was only pressing clear data first the first 2 times I tried this, and checked for the update and nothing happened, but then when I went back pressed the force stop button for Google Services Framework, and re-checked for the update I got the update right away.
http://www.ijailbreak.com/how-to/force-ota-system-update-android-phone/ <---- This is the website I found saying how to get the Update.
and this is the screen you should get after you press Install now after recieving the update
If your still receiving the error message you best bet is to take your phone into your sprint store. The phone might be missing a file needed to complete the update, they can update your phone for you there and they cant tell you to wait for the notification or some garbage now that you've attempted the download without any success lol.
Tried it, at first it didnt update. Went through the process again, turned my phone off, turned it back on and i see "Android system update... Downloading .348.7MB".
.. Yes it worked. Thanks a bunch!
Since both Sprint & Samsung CS reps were giving me the run around regarding when I'd get my OTA update, I did the process suggested in this thread. YAY - It worked on the first try and it's WONDERFUL so far! The only thing that wasn't working correctly is my Accuweather widget. I just cleared the cookies and forced closed the app (settings > apps > all tab > weather wiget main > clear cookies > force close) and everything is fine now!
Now if they can only solve my 4G LTE issue in my neighborhood. They claim I'm smack dab in a good area for LTE; however, my GS3 thinks otherwise....