Can someone give me a quick guide for installing ICS on an SGH-i777? Also, are there any problems with the calendar or anything else?
Unlikely that this exists. You'll need to flash a ROM the phone will consider custom (even if its actually the stock ROM not really sure if that is possible given the large number of S2s in America) so you need to unlock the bootloader first then flash your phone. While I've never needed to unlock the bootloader on a phone (though from what I've seen its fairly painless) the actual flashing is relatively simple and if you're careful you can always go back to the same ROM you had before (note down build number etc. and download it before you flash any ROM)
try checking www.sammobile.com you will have to sign up but you can look there for your phone's rom. and you will need to use odin to install it
