You're probably getting used to OEMs being conveniently vague about dates of Ice Cream Sandwich rollouts. Well, Acer has seen fit to set the record straight and clue everyone into the update schedule for the Iconia Tab A100 and A500 Android tablets. Both devices will begin getting the update on April 27, which is a mere 10 days from now. The A200 got its update way back in February.
Update: Mexico and Brazil updates clarified:
The aforementioned April date is only for the US variant of the devices, though. Latin America is actually getting its updates under way a few days earlier, but sadly, Iconia A100 owners in Canada will have to wait until May 3. Mexico and Brazil will be left hanging until some nebulous "mid-April" date that might be Acer's way of saying "eventually."
The Android 4.0 update (early versions of which leaked in February) will bring a faster interface, Acer's Ring feature for quick access to apps and settings, and better image capture. You can start mashing the update button very soon, but until then - patience.