All four of the current smartphone operating systems support the core promise of the device: quick access to calendar, contacts, e-mail and the Web, as well as the ability to handle third-party apps. That said, each appeals to a slightly different user.

The Corporate Exec
Windows Mobile for PocketPCs
This workhorse of an OS invariably arrives on a large PDA-centric device that´s perfect for editing documents and browsing the Web. With Virtual Private Network software, it´s the most likely to let you fetch your work e-mail. It´s not all business, though. The screens are typically big enough for portable video, and some devices can play songs downloaded from sites such as Napster.

The Light User
Windows Mobile for Smartphones
The Smartphone edition is built for quick one-handed access to your address, contacts and e-mail but has no touchscreen capability, so replying to e-mail is somewhat cumbersome. There are also fewer applications written for this platform, but they´re mostly consumer-oriented-games, health monitors and foreign-language
dictionaries, for example.

The Multi-Tasker
Symbian is generally better than the others at handling multiple tasks at once-say, streaming music while playing Scrabble and fielding a call. There are a variety of flavors: Symbian Series 60 covers the basics, such
as calendar, e-mail and Web apps. Symbian UIQ adds touchscreen data entry, and the powerhouse Series 80 adds support for widescreen displays and Qwerty keyboards.

The traditionalist
Palm OS
The first successful PDA operating system, Palm may be the most familiar to people. With a legacy of applications written for Palm handhelds, you can find just about anything you´d want for work or play.
Currently only a few smartphones use Palm, but we´re likely to see many more Palm smartphones when version 6 of the OS comes out later this year.