It’s a cell phone. It’s a computer. It’s the two invaluable companions of the modern executive in one. DualCor Technologies next month will unveil the cPC, a full-fledged handheld Windows XP computer that also comes with a built-in smart phone that runs Windows Mobile 5.0. The cPC is 6.5 inches long, 3.3 inches wide, 1.2 inches thick and has a 5-inch diagonal screen.