A new device will allow hand-held computer users to switch from writing on paper to their screens -- without grabbing a different implement for each. The PenCap Stylus -- scheduled for release in first-quarter 1999 -- converts any ordinary pen into a stylus and back again. It fits directly on the tip or back end of the pen, with a triangular grip and off-center tip. The new stylus is a product of Concept Kitchen, a creator of accessories, software, and information for hand-held computing. The firm also makes the FingerTip Stylus. The PenCap Stylus will sell in six-packs for a suggested retail of $19.99, in most retail stores where Concept Kitchen's other products are found -- such as Micro Center, Fry's Electronics, Electronics Boutique, and Staples. Or it can be purchased at the firm's Web site.