A new Ice Cream Sandwich ROM has surfaced for Galaxy S II (I9100). The new version I9100XXLPH is based on Android 4.0.3 and is fairly new with the build date of February 9. As far as the firmware goes, it is reported to be faster than the previously leaked ROM with improved battery life and TouchWiz overlay.
Users comfortable with flashing their devices can give it a try from the forum link below.
As for the official release, Samsung promised to release the Ice Cream Sandwich update in Q1 2012, which means the update should be out before the end of March.