AT&T may be late to the LTE party, but when it finally arrives, it’s bringing Houston along for the ride.

Houston’s among the first five cities that will be able to sign in to Ma Bell 2.0’s next-generation data network. The company said today it will launch LTE this summer, but didn’t give a firm date. Rumors have put the launch sometime in June, but AT&T has not confirmed that.

Houston is one of three Texas cities – along with Dallas and San Antonio – that will be early adopters on the LTE network. Atlanta and Chicago are also on the list.

Currently, AT&T has upgraded its existing HSPA data network to HSPA+ and is touting it as 4G. But its speeds are disappointing in some areas. In my print column for this week, I wrote about the Samsung Infuse 4G smartphone, which works with AT&T’s HSPA+ network. In my tests, it often was slower than my 3G-based iPhone 4.

LTE stands for Long Term Evolution, and it’s expected to be the primary way mobile data and voice services will be handled in the future. Verizon already has an LTE network, where download speeds vary between 8-20 Mbps. There have been whispers that Sprint may switch to the technology, though that the moment it’s sticking with WiMax.

T-Mobile has opted to go with HSPA+, but it’s getting much better results than AT&T. T-Mobile already sells devices capable of download speeds of 21 Mbps, and has announced a USB data stick for notebook computers capable of 42 Mbps.