The earlier promise by Sony to roll out Ice Cream Sandwich to Sony-Ericsson Xperia handsets is currently in progress. ICS updates to SE Xperia Arc and Xperia Neo are now slowly being rolled out to devices.
We checked this update on one of our Xperia Arc devices and can confirm the update being detected via Sony PC Companion.
The update is not OTA so you will have to down load PC Companion and install it on your PC to run the update.
Here’s a thorough rundown of the changes made along with the ICS update.
Note though that not all Xperia Arc and Xperia Neo might detect this update but you should keep a close look and try it with PC Companion in the next few days.
Note: You can check this listing of SI numbers for Xperia Arc to see if your device is included already.