For fleets, it will help cut down the amount of time and money spent returning to offices to do work and attend meetings, ensuring drivers can stay mobile but still fully in touch with events at base.
The system, called wireless local area networking (LAN) will be rolled out across the country over three years, and will mean that drivers with the right equipment and method of payment will be able to access the internet without the need to plug into sockets, or use cables.
Wireless LAN 'hotspots' will be situated in public places, and can be accessed as long as the user is within 100 metres of the site.
Pierre Danon, chief executive officer of BT Retail, said: 'We intend to build a national network of access points around key public sites, all within reach of business travellers, commuters and other users.'
The major advantage of Wireless LAN is that there is no need for cabling or digging, and it gives the same speed internet connections as desktop PCs.
Danon added: 'It complements mobile services for those who are 'on the pause' rather than 'on the move'.
By June next year, 400 sites should be up and running, and BT is in discussion with Costa Coffee, all UK airports and Welcome Break service stations about adopting the service.
BT expects the system to bring in £500 million a year in revenue by 2007.