HP's iPaq Mobile Messenger is a wireless handheld that combines mobile phone and GPRS data capabilities with built-in satellite navigation, plus a mini keyboard to make messaging easier. This combination of features makes it well suited for mobile workers, especially sales staff or service engineers who travel frequently.

The Mobile Messenger comes in two versions: the hw6515 features a 1.3 megapixel camera, while the hw6510 has no camera and costs slightly less. Both can be purchased SIM-free from HP, but most firms will probably acquire the device through a reseller or carrier with a mobile service agreement.

We found the Mobile Messenger performed faultlessly as a phone, though many users may prefer to use either a Bluetooth headset or the supplied earbud headset when making calls, as the iPaq is bigger than most mobile handsets. Many of the device's other functions are similar to those of Pocket PC PDAs.

HP's iPaq Wireless control panel allows users to turn both the GSM/GPRS and Bluetooth radios on or off with a single tap of the stylus.

Both Mobile Messenger models are based on a 312MHz Intel PXA270 processor with 64MB RAM. The 3in display is square instead of rectangular to make way for the qwerty keypad and displays 240x240 pixels. Secure Digital (SD) and Mini SD card slots are available on the right edge of the device. The keys on the Mobile Messenger's keypad are arranged in a curving layout that takes a little getting used to. However, we soon found we could enter text or edit Pocket Word documents at a reasonable speed using thumb typing. The device also has a five-way mini joystick controller.

Navigation facilities are provided by an integrated Global Positioning System (GPS) receiver and built-in copy of the popular TomTom Navigator software. This provides a 3D view of the user's position on a map, and gives spoken directions to required destinations with a choice of voices.

However, maps are not included; users can download one city map from the TomTom web site for free, but additional city maps cost £7 while the entire Western Europe map set costs £139.

The built-in GPS uses a technique called Assisted GPS to speed the location finding process, using satellite orbit data downloaded from the internet. This data must be refreshed every couple of days, but updates seem to be free.

The Mobile Messenger comes with a 1200mAh removable battery that should provide at least a full working day between recharges, according to HP.

As well as the Pocket versions of Word and Excel, the Mobile Messenger comes with many applications, including PDF and PowerPoint viewers from ClearVue, HP's iPaq Backup, and the iPaq File Store tool that lets users access unused space on the device's non-volatile Flash ROM.

The camera on the hw6515 model captures images at up to 1280x1024 resolution, and can also record short video clips.