The next step is to enhance the wired portion of the network that connects all of the towers. This will be mostly fiber. Charlotte, Chicago, Dallas, Houston, Los Angeles, and Miami will be the first cities where the HSPA 7.2 network is activated.
This upgrade also sets the stage for the next generation network, LTE, though that won't start until at least 2011.
The question is will AT&T get the network upgraded fast enough to forestall a massive exodus to a competing network should they lose their iPhone exclusivity? The iPhone isn't the only smartphone on the carrier's network, but it is far and away the most popular and has an unusually high percentage of big bandwidth consumption and is largely the cause of AT&T's wireless woes. Hopefully consumers will start to see the benefits of the new network soon.