We have covered this before when Samsung Italy has confirmed ICS update for Galaxy note and Galaxy S2 over twitter. Now This is official on Samsung Tomorrow official Global Blog. First update will start rolling in the first quarter of 2012 for Galaxy SII and Galaxy Note, other will follow soon. Recently we have seen an Alpha leaked ICS rom for I9100, which clearly indicates that Samsung is working hard on ICS update for Galaxy devices.
According to Samsung Tomorrow blog below device will surely get ICS update -
GALAXY S II,
GALAXY S II LTE,
GALAXY Tab 10.1,
GALAXY Tab 8.9,
GALAXY Tab 7.7,
GALAXY Tab 7.0 Plus.
Google has already started ICS update for Nexus device from last week.
If you want to have a feel of Android 4.0 Ice cream sandwich(ICS) on your Galaxy S2 I9100 then you can check I9100XXKP1 guide.