Someone at Samsung and/or AT&T must be just giving this stuff away, and whoever you are, we thank you. After leaks of the official Android 4.0 ROM for both the Galaxy S II and the Galaxy S II Skyrocket, the same update for the plus-sized Galaxy Note has also appeared. You can download it now over at RootzWiki. The ROM in question is only for the SGH-i717, AKA AT&T's customized LTE version of the Note hardware - it won't work on international GSM versions. The leaked software runs Android 4.0.3, and doesn't appear to have any significant issues.
This is the real deal update, straight from Samsung (via some community-minded tipster) and includes Samsung's TouchWiz. Of course it's a little different that the standard version, owing to the Note's relatively massive screen size and adjuster ergonomics, but seems to include all of the current features plus the standard goodies from Ice Cream Sandwich. The download comes in a Windows EXE, so you'll need to use the Odin method from a desktop or laptop running Windows. A ZIP file of the update, flashable from your custom recovery of choice, should be hitting the standard Android ROM and forum sites within a day or so.
Of course if you're not a fan of TouchWiz, there's plenty of stock and slightly modded ROMs out there for the Galaxy Note... all of which should be improved very soon by the addition of a sanctioned ICS kernel. Popular ROM families like CyanogenMod 9, MIUI 4 and AOKP all have representations on the hardware, though not all are "official" and not all may be available for both major versions of the hardware. Samsung has planned to upgrade the international Galaxy Note with ICS sometime this quarter, and AT&T's update will go out at some point, though they haven't said when.