*with full sarcasm intended*
What???? I thought they were announcing the Verizon iphone today???? hahahha. Even the new iPad is dedicated to AT&T.
Not at all. Jobs specifically said that the 3G version of the iPad would be sold unlocked and without any commitment to any wireless carrier whatsoever. If your wireless carrier offers a data plan that you're willing to pay for, and has the ability to use GSM Micro SIM cards (not sure what they are, as opposed to normal GSM SIM cards) then it should just work with the iPad.
The technical specs for the iPad confirm that it cannot use T-Mobile's 3G frequency. However, it is completely compatible with T-Mobile's GPRS and EDGE technology. So if you happen to find a data plan from T-Mobile that suits your needs, you should be good to go with Apple's full blessing. From that perspective it definitely isn't "dedicated to AT&T".
That being said, they also announced a couple of prepaid, contract-free 3G data plans that AT&T will be offering for use with the iPhone. So I'd say that it "strongly favours AT&T". I'd be interested to see if T-Mobile chooses to compete with AT&T on price in that arena.
However, since Verizon and Sprint use incompatible technologies, they're still out in the cold.