Samsung released their upgrade plan for United States tablets. All Wi-Fi Galaxy Tabs that are currently on Honeycomb (3.X) will receive an update to Ice Cream Sandwich (4.0). On AT&T, both the Galaxy Note and the Galaxy Tab 8.9 will be upgraded to Ice Cream Sandwich. On Verizon, the Galaxy Tab 10.1 and the Galaxy Tab 7.7 will receive the update to Ice Cream Sandwich. Samsung has not released any information about tablets on other US carriers though.
Samsung did mention that they were still talking with T-Mobile about their upgrade plans and will update us when they have figured everything out.