Sony gives an update on the Jelly Bean release schedule

The first phones to get the Jelly Bean update are Xperia T, TX and V. The roll out will start in February and should be completed by the end of March.The next phones to get the Jelly Bean update is the Xperia P, J and go. Sony will start the updates for those at the end of March.
The last four phones to get Android Jelly Bean are Xperia S, SL, ion and acro S. The rollout for them will begin a few weeks after the second batch of phones get the Jelly Bean.
Here`s  the quote about the Xperia U, sola, miro and tipo:

"The quality of Xperia's software experience is dependent on a number of factors including: screen resolution, hardware platform and RAM. In the case of Xperia go, this combination came together in a way that meant the user experience running JB was not adversely affected.
Unfortunately, in the case of Xperia tipo, Xperia miro, Xperia U and Xperia sola this wasn’t the case – so we made the decision to keep them on Ice Cream Sandwich."
This one is about the arc S:
"Xperia Arc S is part of our 2011 portfolio, which won’t be upgraded beyond ICS. The reason being – user experience is at the heart of our product development and support; after thorough evaluation, we concluded that the user experience for our 2011 Xperia smartphones will be superior if they remain on Ice Cream Sandwich versus being upgraded to Jelly Bean."