Cingular said on Wednesday it would begin selling a mobile phone running the latest Microsoft software for mobile phones. The Cingular-branded 2125 Smartphone, made by High Tech Computer went on sale for $199 on Wednesday. Cingular is aiming the phone at both business and consumer customers. It will be the first U.S. phone based on Microsoft Windows Mobile 5.0 software that has a typical cell phone dial pad instead of a tiny computer-style keyboard.