Laptops have long been popular because they are portable and easier to transport compared to a desktop PC. Now a whole array of handheld computer cell-phone combinations are posing serious competition.
Devices such as Sony's Clie handheld computer, Palm's Treo 600 mobile phone-computer and others from Hewlett-Packard and Dell give users functions they normally enjoy on laptop computers. Apple's iPod has many features associated with handhelds.
They allow people to send e-mail, check the internet, play MP3s and movies, schedule events and many other functions. And with the number of transistors doubling every 18 months on chips (Moore's Law), these devices are bound to get better. Source