This is not happening. This is a big crap-storm of confusion over a technical term. Verizon will be releasing a software update to unlock this phone for global gsm service. The damn service reps at Verizon don't know the difference between gsm unlocking and bootloader unlocking.
I'll repeat: the bootloader is never going to be unlocked by Verizon. Samsung could possibly release a tool like HTC did, but Verizon isn't going to do anything. Since the GSIII is only software encrypted, instead of hardware encrypted (like Moto devices), there is reason for hope that someone in the community will deliver legit bootloader workaround...but don't get your hopes up.
This is especially painful for me since I had intended to activate this device for myself. With the bootloader issue unresolved at this time, I instead got my wife all set up and she's incredibly happy. I'm absolutely blown away at how fast and fluid the GSIII is. Even with my Nexus running Jelly Bean, it just looks slow and tired next to the GSIII. Battery life is phenomenal as well. If a bootloader workaround happens, my Nexus is gone and I'll be picking up a GSIII for myself.