It seems like AT&T is getting a Tegra 2 Android phone from Motorola as early as January 2011. The phone is called Motorola Olympus, and it probably won't have a 4G chip in case you were asking for one. Obviously, it will be a while until AT&T will have a 4G network, so no need to make 4G phones for their network.
Here's the leaked information that has led to this rumor:
OEM : Motorola
Device : Olympus in preproduction
Type : Phone
Chipset : nVidia Tegra 2
ABI : armeabi-v7a
PRODUCT : olyatt
FINGERPRINT : MOTO/olyatt/olympus/olympus:2.2.1/OLYFR_U4_0.145.0 /*********:userdebug/test-keys
MEMORY : 837332 kB
CERTIFIED? : NO
UserAgentString : Mozilla/5.0 (Linux; U; Android 2.2.1; en-us; MB860 Build/Blur_Version.4.0.1450.MB860.ATT.en.US Flex/P013) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1
I'm sure Motorola will have a Tegra 2 phone ready for Verizon and perhaps other carriers, as well.