PDAs: for a networked world.(personal digital assistants)

The personal digital assistant is evolving in ways that make it easier to use and better able to connect to the Internet and to other devices.

Two types of PDA dominate in sales to U.S. consumers. Seventy percent use the Palm operating system (OS): the rest use Microsoft's Pocket PC software. Here's what the latest models offer:

Designs tailored to the user. Some of the latest models can easily be operated with one hand, wirelessly send and receive e-mail, or readily fit into a pocketbook or shirt pocket. Among Palm OS units, Sony has taken the design lead with built-in cameras and bigger screens.

Better power management. Some Pocket PC units have laptop-like power-saving schemes, but in our tests, only the Toshiba e805's made a difference: You can extend its battery life for an hour by slowing the processor's speed.

In some cases, fewer choices. Power-hungry color displays have nearly displaced monochrome; nonreplaceable batteries are standard for Palm OS models.

HOW TO CHOOSE

Consider your ties to a computer. Pocket PCs provide a Windows-like interface that allows simple PC-to-PDA file transfer with drag-and-drop capability. They're also better than Palm OS models for setting up a Wi-Fi (wireless) e-mail connection. Most have replaceable batteries, along with accessible flash memory to which you can back up data.