Sony Ericsson has become one of the first manufacturers to release an early Android 4.0 Ice Cream Sandwich ROM, hot on the heels of Huawei, which uploaded a test build for the Honor a couple of days ago. The alpha ROM released today supports bootloader-unlocked Xperia Arc S, Xperia Neo V and Xperia Ray handsets, and is intended to give developers a preview of what's to come. Sony Ericsson has of course already confirmed that the entire 2011 Xperia line will be updated to Ice Cream Sandwich in the months ahead.
Certain functionality is limited in the alpha ROM, most likely for legal reasons -- there are no Google apps included, and you won't be able to make phone calls, pretty much eliminating the possibility of using the ROM as your daily driver. We suspect some enterprising folks will be hacking away at this soon enough though, with the intention of removing some of these restrictions.
If you're not quite brave enough to flash this ROM on your own device, Sony Ericsson has also shot a brief video walkthrough showing off ICS features like the lock screen music controls and task switcher. You'll find it embedded right after the break, while instructions for flashing the alpha ROM can be found at the source link.
Source: Sony Ericsson Developer World
YouTube link for mobile viewing