Wow, the news today is AT&T will carry the Galaxy Tab as reported in September but at $50 more than other wireless carriers. Verizon, Sprint, t-Mobile, all have a no-contract price of $599 so if you really want AT&T you'll pay extra. We'll see what the total cost is when compared to other carriers. There is no activation fee for the Tab or iPad so maybe this softens the price difference somewhat. The bottom line is the iPad 3G is cheaper than the Galaxy Tab 3G at the AT&T stores, and that will be a tough sell.
AT&T has an exclusive deal with Apple on the iPhone and until recently the iPad. While AT&T clearly supports all OS types on phones and now tablets you won't get a price break on the Tab at AT&T - same price as the iPad.
Too bad there is no wi-fi version yet!