Personal Digital Assistants (PDAs) are replacing daytimers and organizers for people on the go who need to look up and record contacts, appointments and other information.

The capabilities of the latest PDAs and handheld computers have been extended to include web access, email, phone and games. Even though the PDA market is only a few years old, there are a lot of choices. With some consideration of your needs, you'll soon have the right PDA in the palm of your hand. PDAs can be subdivided into handheld and palm categories based on the presence or absence of a keyboard. Handhelds are larger in size and have full keyboards, whereas palm devices don't have keyboards and are stylus or pen operated. Be aware that sometimes PDA is used to mean only palm devices while the term handheld is often used to encompass all handheld computers.

Palm computers are better geared for users looking mainly to store personal information like calendars or contact lists. Instead of a keyboard, palm units use a pen-like stylus with handwriting recognition software and a touch screen for data input. Alternately, an onscreen keyboard can be used where you tap each letter with the stylus. Their pocket calculator size and light weight make them easy to hold in one hand and very portable.

On the other hand, if you plan on doing a lot of word processing and internet surfing, you'll need the extra computing power of a handheld. These computers have a clamshell design with a keyboard and usually have a larger screen which is touch sensitive. Some handhelds can be as small as palm units, others the size of a typical paperback. Professional models are as large as a hardcover book.

PDA screens are LCDs (Liquid Crystal Displays) like those found in notebook computers and flat panel displays. Early on, you could only get PDAs with monochrome screens, but colour is now available. Monochrome screens can be strictly black and white or display anywhere from 4-16 shades of gray.

Most PDAs are monochrome models, but colour is becoming increasingly popular. Some colour screens can display thousands of colours. Of course, you'll pay more for a colour screen, and it will drain the device's batteries faster. Don't get a colour screen if you plan on using your PDA outdoors because the screen will wash-out in direct sunlight. It's also advisable to get a screen with a backlight which makes it easier to read under a variety of lighting conditions including the dark.