AT&T has officially started mapping their 4G HSPA+ coverage on their website. Currently, the list is limited because it only includes the full cities which have undergone the backhaul upgrade. AT&T has deployed HSPA+ to 100% of the network, but if the site you are connected to does not have "enhanced backhaul" you will not be able to take advantage of 4G speeds.
The areas include
●Bay Area, CA
●Los Angeles, CA
To view the coverage for yourself visit www.att.com/network
. Hit the coverage tab, then hover over the map until the cities with 4G coverage appear.