as many of "dedicated" AT&T customers know, when a new OS comes out for our beloved android devices, AT&T has to "tweak" it to their liking to "run the way they want it to run". once that's said and done they'll do the OTA update.
i'm sure the update will come 6-8 months after it released. give or take a few months.
on a good note, i have seen images and videos on how ICS works on other (if not older) smartphones and it looks pretty snazzy.