2. Pick Your System

Like a smartphone, what defines a PDA phone is the operating system it runs, the applications that includes and the extra applications you can install. Palm has been producing PDAs for several years and the Palm OS and the many apps that run on Palm devices are familiar to many users; the Treo 680 and 700p add phone features to these - although the Palm 700w runs Windows Mobile Pocket PC Edition and from next year Palm will switch to a new Linux-based OS. Palm's email client supports AOL Mail, Apple's .Mac, EarthLink, Gmail and Yahoo Mail but not Hotmail; the VersaMail app supplied by many operators includes Exchange ActiveSync support, but otherwise you need to pay for GoodLink for push email. The Web browser is fair but a little dated.

Windows Mobile Pocket PC Phone Edition is the familiar Pocket PC OS, with added phone features. The phone tools aren't as slick as those on Windows Mobile Smartphones except on the Palm 700w, which adds its own dialer on the front screen so you can just start typing a name to get numbers to dial. Mobile versions of Word and Excel let you create and edit documents in standard Office formats, while you can only view PowerPoint documents. Outlook integration is excellent, including pictures of your contacts, and you get true push email. Pocket Internet Explorer reformats Web pages to fit them on screen automatically.

Symbian PDA phones like the Sony Ericsson P990, Nokia 9300 Communicator and Nokia E62 (the E61 in the UK) have the same underlying OS but often quite different user interfaces. They usually come with software to view and edit Office files as well as the standard PIM tools. The push email client varies; there's a basic POP and IMAP client built in but GoodLink, Intellisync, Visto, DataViz RoadSync, Consilient and Blackberry Connect all work on Symbian. The browser also varies; often it's a mobile version of Opera but the Nokia E62 has a particularly good browser, which formats standard Web pages particularly well and has a thumbnail view of the page for scrolling through (or to help you find pages in the history). Even so, you're still not going to be able to use all the Websites you visit fully-for that you'd need an ultra-mobile PC instead-but as with all these handhelds you can look at standard Websites rather than only ones that are tailored for mobile viewing.

Blackberry does a lot more than email but it performs best with an enterprise connection; consumers who don't run their own Web server have to sync calendar and contacts from a PC or Mac and don't see folders inside the inbox. The browser supports JavaScript though it's off by default for speed and pages are reformatted, again for speed, as are Office documents and PDFs - which you can view but not create. There are a number of applications for Blackberry, but far fewer than for Palm and Windows Mobile devices.