The first smartphone running the long-awaited Windows Phone operating system was unveiled this morning in Japan. The manufacturer: Fujitsu-Toshiba, who plans to bring the device to Japanese stores and carriers in September. It's not expected to come to the U.S.

The phone, known as the IS12T will be the first device to run the major revamp of the Windows Phone operating system to version 7.5, an update codenamed "Mango." Coming about a year after the original launch of Windows Phone, Mango brings with it several new features (), including multitasking and a Groups feature that has deep integration with social networks like Facebook and Twitter. It also has powerful voice-to-text features. (For the full run-down of Mango, check out , or click on the slideshow below.)

The IS12T has other features that go beyond the new OS. The phone is said to be water- and dust-proof, and boasts both 32GB of storage as well as a camera with a whopping 13.2 megapixels. Its processor will be a 1GHz Snapdragon chip from Qualcomm. Users will also be able to use the phone to work on Microsoft Office documents as well as share data through Microsoft's cloud service, SkyDrive.

Microsoft officially unveiled Mango in . The market share of Windows Phone is relatively small compared to other major OSes like Apple's iOS, Google's Android, and RIM's BlackBerry, pegged at only 2 percent of all smartphones in use, according to data from Millenial Media. However, IDC predicts that Windows Phone will of the market by 2015.

Other partners making Mango Windows Phones include HTC, Samsung, Acer, ZTE, LG, and of course Nokia, which announced a major strategy shift to Windows Phone in January. Nokia is expected to unveil its first Mango phone, possibly called the in October.

As for the IS12T, it'll be on Japanese carriers KDDI and Okinawa Cellular. No prices were announced. The unveiling comes a day after it had sent the final Mango code to manufacturers. You can watch a video report on the Tokyo launch event from Network World below.