Here is a video overview of the Samsung Galaxy S2 running Android 4.0 Ice Cream Sandwich. You will only minor UI changes in the new update when compared to Gingerbread.Samsung has retained most of the TouchWiz customization.
You can also see all currently running apps by long pressing on the home button and you can swipe to close the apps in ICS fashion.The browser seems a bit faster. We also compare the S2 to the Galaxy Nexus in the above video. This update will be coming soon to Galaxy S2 devices.