You leave the office ready to see a client, and you hesitate. You ought to have something with you. The client's address? A document from your main computer, perhaps? A spreadsheet for sales, or perhaps some device for picking up your emails?

To some it begins to sound as though they need to have a laptop computer with them, preferably with a GPRS phone for a decent internet connection. There can be good arguments for that and it's covered elsewhere in this issue. The alternative, though, is to carry a computer in your pocket: one of the so-called PDAs (Personal Digital Assistants), often referred to as organisers, but most of which are capable of doing a great deal more and which can be a good deal cheaper.

It's odd, then, that according to research organisation ProData, only 3% of small and medium-sized businesses were using the things in 2001, forecast to rise to only 6% by 2004. They are bigger in some business sectors than others: you're more likely to have one supplied by your employer if you're in business services, where the devices have 14% penetration, while 20% of companies spending over £500 on mobiles have also bought PDAs.

Whether or not you need a PDA as opposed to a laptop - or in addition to one - will naturally depend on your needs and your budget. It often surprises people that if they need to do some word processing, spreadsheet work and emailing, then most modern PDAs will do the jobs without a problem after the addition of a few accessories.

There are three basic types of PDA: those based on the Palm operating system, the ones from Psion and the ones based on Pocket PC from Microsoft. If you want a colour screen you can pay for it, but the main concern for the smaller trader should be how much a device actually does. In this respect the monochrome models from Palm, Handspring and others offer good value; Palm has 50% of the market.

In spite of not using the Microsoft operating systems and software, a Palm will happily synchronise all of the appointments you enter on to it with your PC, take Word and Excel documents, and even sports a book reader, if you care to read books on a screen that small. Expect to pay £100-plus for a basic model which will do all of that. A smaller, more powerful version, the M505, will cost more than £300. Handspring also uses the Palm operating system and its organisers tend to be slightly cheaper.

The second most common system is Microsoft's Pocket PC. This is the one you get on the Compaq iPaq and products from Toshiba and Hewlett-Packard. But people looking for bargains should stop here: there's precious little under £300. The reasons are numerous. First, the software applications that come preloaded are Microsoft products which will integrate seamlessly with your copies of Word and Excel on the desktop (although the version of Microsoft Money that's preloaded will only exchange data in dollars), not that there are many quibbles with the efficiency of the third-party products on the others.

Second, there is generally more memory on the Pocket PC devices: the starting point is 32kb rather than Palm's 8kb on the M105. It needs this to power a look and feel that will be familiar already to Windows users: full colour, a picture viewer and, on most models, a microphone that will take your voice memos and transfer them to your PC so you can play them back in the office. You'll also be able to play MP3 and Windows Audio format music and other sounds. And there's an earphone socket - not that businesspeople will want to pay over the odds for entertainment.

Both Palm and Microsoft devices have attracted the accessory makers with executive cases, extra memory and other items. The most useful is probably the optional keyboard from either the PDA's manufacturer or more cheaply from a third party like Targus; expect to pay £80-plus for these. They also attract a lot of third party software: maps are available for both, and Dixons has recently started selling a docking station for cars so that the iPaq can act as an in-auto mapping system.

Psion, with its Epoc system, basically invented the pocket organiser market when they really were just organisers. In spite of pulling out of selling to consumers last year, the company remains committed to businesses and will sell its Series 5mx and Series 7 to anyone who needs one. Again, these link to common office applications through a cable, and unlike the competition they have their own keyboards. Psion is less interested in bells and whistles than a lot of its competition, reasoning that employers won't want their employees playing games or listening to MP3s, so it doesn't supply these functions (although games are available from third parties).

The business value is very straightforward, as Andrew Fisher of communications company Redhouse Lane explains. "The greatest power of the PDA for the business is that it gives you the ability to keep yourself organised, synched and use those little 10-20 minute parts of the day to do those things that get lost or you always put off."

PDAs don't suit everyone. Although they can carry presentations, the screens are hopeless for more than one person and if you're going to carry a monitor and cables around for your presentation, then you might as well carry a laptop. If your need is for your own information and documents, or info you can share verbally with others, then the smaller and cheaper PDA is something you should seriously consider.

That's what I call fast food

Whenever you pop into your local supermarket or grocer for some sausages or yoghurt, you probably never stop to consider how they got there in the first place.

UK-based chilled food distributors like Kerry Foods now routinely order deliveries through hand-held Psion Teklogix computers. The days of written orders and faxes to delivery depots have been consigned to the past. Executives at Kerry Foods are keen to harness new wireless technologies to give themselves "mobile advantages" in what is generally regarded as a highly competitive marketplace.

The Psion computers enable the firm's van salesmen to take orders electronically, calculate discounts, and to print out invoices on the spot. The mobile computers store sales histories and keep the sales force informed about all the latest promotions.

At the end of the day instead of struggling back to the office with mountains of paperwork, the sales force put their hand-held computers into cradles; the individual orders are electronically consolidated on to one PC and sent via ISDN lines to a central distribution hub. The food is dispatched the next day.

Mike Skinner, business development manager, cannot get enough of the new technology which he sees as a powerful integrated sales tool which sharply reduces errors. "What it allows us to do is to manage the business effectively," he says." It makes us more productive and efficient." By introducing a smoother flow of information into the business, he argues that sales managers can download and access data on customer orders far quicker so the business can enjoy a better idea of how it is performing against targets, which helps when it comes to projecting future sales.

Most of the products that Kerry Foods distributes in its temperature-controlled vans can have a shelf life as little as three days and so efficient delivery and accurate forecasting is essential. The introduction of the hand-held computers has not only generated administrative savings but has ensured that customised products can appear on the mobile computer lists which match sales agreements.

But what are the shortcomings of this new approach? "It can be quite daunting for someone not used to a computer," Skinner says, explaining that extensive training is required. "The problem is when they go down. Then you have to rely on paper. It typically happens if the battery suddenly dies."

Kerry Foods is working in partnership with Psion to consistently update software, which obviously incurs more costs. "It's an evolutionary process," Skinner explains. "Bolt-ons have been added."

Guy-Franck Nakach, managing director of morthern Europe for Psion Teklogix, believes that mobile wireless solutions are not beyond the budgets of most SMEs, although he admits that it requires a significant upfront investment before a company sees any returns. Analysts in this space recommend that companies of all sizes review the processes that are critical to their businesses before adopting wireless solutions. It's largely a question of assessing whether or not those processes could deliver advantages to the business if there was a swifter exchange of information.

Nakach believes companies in most European countries are generally reluctant to embrace mobile solutions for cultural reasons. "I don't think the UK market is behind the continent at all." He says there are similar barriers to wireless adoption in France and Germany. "The interest is there. It is proven and yet SMEs seem to hesitate to invest. It represents a new way of working and different habits." At this stage, he believes it will only be the companies who are prepared to cross a certain threshold in the cultures of their organisations that will gain the benefits of mobile working.

The area of after-sales management is where Psion believes mobile devices could be of most benefit. Proponents of this new technology suggest that in the future it could become a severe competitive disadvantage if sales representatives have to go back to the office in order to fulfil a customer's requirements, rather than doing it there and then with a mobile computer.