Sprint has announced that its latest Windows Phone smartphone launch will be the Lumia 635. The phone features a ClearBlack 4.5-inch LCD screen, interchangeable back panels, 5-megapixel main camera with LED flash, and Nokia apps. It is powered by a quad-core 1.2GHz Snapdragon 400 processor with 512MB of RAM, 8GB of internal storage, and supports microSD cards up to 128GB. Boost Mobile and Virgin Mobile USA will begin selling the Lumia 635 online on Dec. 23 and in stores Jan. 9 for $99.99. Sprint will launch the Lumia 635 for postpaid customers starting on Jan. 16, though pricing for the postpaid version has yet to be announced. This makes its release the first Microsoft-branded Windows Phone smartphone on Sprint.