AT&T this morning unveiled its lineup of Windows Phone 7.5 handsets, which will ship to customers in the fourth quarter. As with last year's initial Windows Phone lineup, AT&T is going with three different devices, from Samsung and HTC. But there's some great additional news: All these devices are based on 4G (at least within the debatable definition of 4G that AT&T uses for its HSPA+ service).

"Our customers love Windows Phones, which is why we've sold more of them than anyone else," says AT&T Mobility Senior Vice President Jeff Bradley. "We're taking our leadership to a whole new level by getting the Mango update to all existing customers and rolling out awesome new Windows Phones."

The new handsets are:

Samsung Focus S

A followup to the best-selling Focus, the Samsung Focus S features a 4.3" Super AMOLED Plus display, 1.4GHz processor, 4G-capable speeds, and a thin (8.55 millimeters) form factor. It also includes a front-facing 1.3-megapixel camera and a rear-facing 8-megapixel camera.

Samsung Focus Flash

The first of a new range of cost-conscious Windows Phone handsets, the Samsung Focus Flash features a 3.7" Super AMOLED screen, a 1.4GHz processor, a 5-megapixel camera, and a front-facing camera.

HTC TITAN

With an enormous 4.7" screen, the HTC TITAN (previously shown here), provides a 1.5GHz processor and an 8-megapixel camera with dual LED flash.

Microsoft also has a post about the new phones, but no new additional details or photos. I'll try to find some.

AT&T also announced that it would be "among the first" to deliver the Windows Phone 7.5 Mango software update to customers of its existing Windows Phone devices (HTC HD7S, HTC Surround, LG Quantum, and Samsung Focus). We'll see how well they follow through on that, but based on AT&T's performance this year delivering smaller Windows Phone updates, I'm not hugely excited about this.

My review of Windows Phone 7.5 will be available soon.