For those who crave zippy-fast data connections on their mobile devices, good news has arrived.  On Sunday, AT&T launched its high-speed 4G LTE network, with the lucky denizens of Atlanta, Chicago, Dallas, Houston, and San Antonio being the first to receive AT&T’s new and improved cellular signals.  If you don’t live in one of the aforementioned cities, don’t fret, as 10 more cities should receive LTE networks by the end of the year.

In recent months, AT&T has been preparing for its LTE launch by releasing a number of 4G-capable cellphones (such as the Android-powered Motorola Atrix and the HTC Inspire 4G), tablets (HTC Jetstream and Acer Iconia Tab A501), and a number of portable USB 4G modems.  Unfortunately, users of AT&T’s most high-profile cellphone, the iPhone, will have to cross their fingers and hope that Apple deigns to include 4g capabilities in their as-yet-unannounced iPhone 5.

So far, it looks like AT&T’s 4G service is running quite smoothly, and quickly, as initial testing of the carrier’s 4G network in Houston by independent evaluator Signals Research found an average of 23.6 Mbps on downloads, and an average of 15.2 Mbps for uploads.  The test was conducted prior to the final installation and activation of all the LTE cellular towers in the Houston area, which means that the network was not running at full capacity, though since the testing occurred prior to the service’s official activation, the network probably also had a very light user load.

AT&T’s 4G LTE network isn’t just of interest for current AT&T subscribers.  Now that AT&T has thrown its hat into the high-speed cellular data ring, all the major US cellular carriers now offer some form of 4G service.  As LTE build-out continues across the country over the next few years, and as users purchase 4G-capable devices, we may begin to see some dramatic changes in how people connect to the Web.  Will home broadband subscribership rates drop, as people migrate to phone and 4G cellular modem technologies? Those interested in making the move now will note that AT&T currently offers four 4G LTE-compatible devices: the HTC Jetstream tablet, the AT&T USBConnect Momentum 4G, the AT&T Mobile Hotspot Elevate 4G (which we covered previously), and the AT&T USBConnect Adrenaline.