AT&T has lagged behind Verizon in getting its 4G LTE network up and running, instead choosing to advertise its 3G network as a 4G network and hope people didn't ask too many questions. But not for much longer! AT&T should have it's first real 4G phone running on its LTE network by the end of the year.
AT&T is waiting until it has at least 50 million potential customers covered by its fresh new network, which should come in the waning days of 2011. They haven't announced what the phone will be, but it'll probably be the Motorola MB865, which is also known as the Droid Bionic on Verizon. The chances of this year's iPhone being LTE appear to be slim to none, unfortunately, but there's always next year.