Samsung will unveil a 4.8-inch Windows Phone 8 device, according to sources familiar with the company's plans. The large screen Windows Phone will be named the Ativ S, as part of a new branding effort by Samsung for its Microsoft-powered hardware. It will include a 1.5GHz dual-core processor, 4.8-inch HD Super AMOLED Display, an 8-megapixel rear camera, and 1.9-megapixel forward facing camera.

We're hearing that Samsung may be one of the first, if not the first to announce a Windows Phone 8 device, and may be preparing to launch the device at this year's IFA 2012. We'll be live blogging Samsung's Unpacked event, so stay tuned for a likely launch later today.

Update: Microsoft just officially announced the Ativ S.