Retailing today is often said to be "Martini-flavoured" or "any3"-anytime, any place, anywhere, a reference to the old television advertisement for vermouth. And, to many, that means going mobile.

"Customer-connectivity is a key retail differentiator that is enabled by m-commerce," argues Jeff Luker, managing partner with the North American retail practice of Accenture, formerly Andersen Consulting.

"This will allow retailers to interact with their customers at the point-of-need, wherever that happens to be. Mobile systems are location-based which lets people know where you are," he adds.

They will also, he says, provide services and information whenever it is needed, and can be accurately personalised.

Using current systems, buying and selling goods over the internet is not particularly easy. Users have to sit in front of a computer, fire up their internet browser, type in the address of a commerce website, find the item or service they want to buy, enter their credit card details and, finally, actually buy the thing.

Desk-based systems are fine when it comes to shopping from home or office, but buying from the car, while sitting on the underground or a bus, or on the way back from holiday will need something more portable.

With a 3G mobile phone, users will be able to log on to the internet without even being aware that they are doing so. The shopping services offered on such sites would let people buy goods and services over the internet on the move, quickly and conveniently.

The reader would be presented with a series of options on the screen of their mobile phone, and be able to pay for the items with an electronic wallet, or perhaps through their mobile phone bills.

A recent survey by Accenture, looking at both US and UK mobile telephone and personal digital assistant (PDA) users, found that one-in-ten of the phone customers and one-in-four of the PDA owners had already used their devices to buy goods. The survey also showed that customers were very happy to receive unsolicited promotional messages as long as they were personalised and relevant.

Current systems give an indication of the potential of the mobile internet. At the Palisade shopping centre in New York, customers can already opt to receive personalised messages from stores via their mobile telephones while they are in the mall. These connections are seen as an important part of relationship building as well as providing new opportunities for additional sales.

Phone-based payment systems are already proliferating: Ahold, the Dutch supermarket chain, is experimenting with a Wap-based payment application; and McDonald's is running a trial in California allowing shoppers to pay for their fast food by authorising payments via their mobile phones.

"These micropayment applications could bring big savings in transaction costs in future," argues Mr Luker.

As well as customer applications, there are also a growing number of trials where store staff are using PDAs to link to corporate websites or other information sources to improve customer servicing for real-world shoppers.

Circle K, the US convenience store, is using the units to improve stock checking from the shop floor while Best Buy, the consumer electronics giant, has found PDAs a more effective alternative to its interactive kiosk network.

"Consumer products are going through a period of such radical change that it is difficult for staff knowledge to keep up with them," says Bradbury Anderson, president and chief operating officer of Best Buy. "They're also fun products so we have to make the in-store experience enjoyable for our customers."

Four years ago, Best Buy won innovation awards for its interactive kiosk system which painstakingly explained all these new digital products to shoppers. "It looked great," says Mr Anderson, "but it didn't work. Customers simply didn't like standing in front of the units, and sales staff were embarrassed to use them as they thought it implied an ignorance of the products on their part."

Best Buy is now equipping its staff with PalmPilots which can be used to obtain additional product information while talking to customers in the store aisles. The unit has a bar code scanner so all the assistant need do is scan the product code and a full specification and availability information will pop up on the screen.

The system includes a location map to help shoppers find what they are looking for. Staff can also input order and delivery details and print out a confirmation slip which the shopper then takes to the cashpoint to pay. The PalmPilots link to the store intranet so at the checkout all the necessary information is available.

"Customers receive full information immediately in answer to queries and are only ever asked about delivery or payment details once," adds Mr Anderson. "And our employees have much more fun dealing with satisfied shoppers."