President and chief executive of the auto giant, Rick Wagoner, said drivers would be able to track stock prices, read e-mail, monitor bad weather and traffic ahead or download music while at the wheel.

At a launch of an expansion of its online operation Mr Wagoner presented a Cadillac Seville fitted up to respond to voice commands such as, "e-mail," "stocks" and "weather".

The reports are then read back in a woman's voice.

He also demonstrated that the car toots if the driver says "horn".

Mr Wagoner said the service operated through GM's existing OnStar satellite communications system, with internet connections which work faster than a comparable one on a standard personal computer.

Help for forgetful parkers

The vehicle system would connect the person inside the car with a Personal Digital Assistant mini-computer which would communicate directly with the OnStar system.

The computer technology could also be used for remote diagnosis if something was wrong with the vehicle or to remotely unlock the car if you lose the keys, he said.

It would also locate the vehicle if the driver had forgotten where it was parked.

The Seville model is having its first public viewing at a car show in Las Vegas this week.

The hands-free technology will allow, initially American drivers, to go online during some of the 500 million hours a week they drive.

Also on Tuesday GM and rival Ford - the world's two largest car makers - both announced plans to link suppliers, dealers and other businesses via the internet.

General Motors will create GM MarketSite, which will be a "virtual marketplace" for products, raw materials, parts and services.

Net initiatives for suppliers

The move represents GM's first major business-to-business, e-commerce initiative, the company said.

"The e-world is a tough world and a competitive world," Mr Wagoner said. "I think we've got the winning hand. Time will tell."

Ford said it expects to launch a web site operated by a joint venture it plans to form with Oracle in the first quarter. The companies are trying to reach a definitive deal.

Both firms said they expect to link with each of their 30,000 suppliers worldwide using their respective systems. GM and Ford spend $86bn and $80bn annually on purchases from its suppliers, respectively.

Oracle Chief Operating Officer Ray Lane said he expects the venture, of which Ford will own a majority, to quickly top $1bn in sales and that it may be spun off in the future.

"This is a joint venture that is what we believe to be the leaders of the automotive business and the leaders on the Internet side," Ford chief executive Jac Nasser said. He added the savings could reach billions of dollars.

GM said their site is expected to help businesses increase efficiency and reduce their operational costs by streamlining purchasing, and will also reduce purchasing cycle times by automatically handling purchase authorisation, accounting and contractual procedures.