Sony have released a beta, aka developer version of the upcoming Android update, Ice Cream Sandwich. The update is for advanced developers, who have extensive knowledge in how to install and switch between ROMs, there fore shouldn’t be installed by any one who doesn’t really know what they’re doing.
If however, you’re comfortable with this, you will need an unlocked Xperia Arc S, Xperia Neo V, Xperia Ray or an Xperia Play running 4.0.2.A.0.42 and an unlocked bootloader. WiFi and Bluetooth are two key features that aren’t included in the beta version of ICS, nor are Google Mobile Services, including Gmail, Google Maps and Face Unlock.