Not yet and it'll be a while before it does as O2 have to 'Test' it frst before they will release it.
What this actually means is they have to put all the bloatware they get paid for on top of the original update and make sure that this doesn't conflict in any way.
This in my experience can take anything from 2-3 months (Sometimes more) while you as the customer get the:
"it's coming soon"
"watch our twitter page" (Who give you the "it's coming soon")
"it's not been released by Sony"
etcetc
If JB really is that important to you i'd suggest getting SIM free OR.
(This will void your warranty)
Go to XDA Devs and I'm pretty sure there will be a .ftf JB to flash from somewhere in the world!
Regards
Gillsfankev
