Sony has released a beta ROM of Android 4.0 Ice Cream Sandwich for their Xperia Play smartphone, and you can test out ICS on your Xperia Play before the final version is released.
Of course the beta ROM comes with the usual warnings, that you should only download and install the ROM if you are an Android developer.
Upon request we’re today releasing an Ice Cream Sandwich (ICS) beta for Xperia™ PLAY, and we’re really interested in getting your feedback on this beta release. As games are such a crucial part of Xperia™ PLAY, we would like to know how well this ICS beta for Xperia™ PLAY works when you’re playing games.
You can download the Xperia Play Android 4.0 Beta ROM form the Sony Developers website, and you can also find out more details about the ROM there.
Source Android Community