Microsoft Corp. said Tuesday that it has sold more than 1 million units worldwide of its audio and video-playing Pocket PC handheld computers, the rival to the popular Palm Inc. line. The handhelds are built by Compaq Computer, Hewlett-Packard and Casio Computer. The company said that it has sold 1 million units of the color-screened devices in less than a year after its launch April 2000. Total sales stand at 1.25 million. That’s still far less than the 13 million devices sold by Palm, which makes up 80% of the total market for handhelds.