Samsung is now rolling out much awaited ICS update for Samsung Glaxay SII G version i.e. I9100G. If you have yet not received ICS update for G version you can get it via Samsung kies. Luckily this update is also available via OTA i.e. over the air.
If you do not want to update to ICS but want to have little taste of of it you can try some Launcher available via Google play which may give you a feeling of android 4.0.3 ice cream sandwich.