Google in their Galaxy Nexus launch event couple of weeks back also introduced their latest Android 4.0 Ice Cream Sandwich OS. Samsung confirmed that Galaxy S II will get ICS (Ice Cream Sandwich OS) update but it will take time. Few deys back ICS code went public and we saw many ports for Nexus S, Galaxy S and Nexus one.
But everyone were waiting for ICS to port on famous Android device the Galaxy S II. Today a developer name @xplodwild have partially successfully ported ICS on Galaxy S II.
The ICS build for SGS2 is still in alpha stages, and audio, modem and quite a few other things are not working. Still I would suggest Galaxy S2 owners to try out this alpha build so as to get a taste of Ice Cream Sandwich, until the official update from Samsung lands.
Check the video of Galaxy S II running Ice Cream Sandwich OS 4.0:
The ICS SDK now on Galaxy S II has also the touch panel buttons but developers claims that in future work they will remove it. The rest ICS looks pretty smooth on Galaxy S II without any lag and other major issues. If you want to port ICS on your Galaxy S II you can follow the guide here