The market leading handheld computer is the Palm Pilot. It's the one you see people pull out of pockets and tap on with a little plastic stylus, and it's well ahead of rivals like Psion and Windows CE. Now the people who brought you the Palm, and sold it to its current owner 3Com, have come out with a rival, the Handspring Visor. It uses exactly the same software as the Palm machines but is much cheaper and has an extremely useful extra feature - a connection slot thatlets you add extra hardware to turn your Visor into a digital camera, music player, mobile phone etc. The Visor went on sale in the UK and Europe last month and the peripherals will be arriving soon from the US. You can buy the complete Deluxe Visor outfit with PC connection and case from the Handspring website for pound;169 or just the Visor for pound;99 (both prices ex VAT), or pick up the Deluxe for pound;199.99 in the High Street from Dixons.