Apple has signed deals with Ford, GM and Mazda to enable 'seamless' iPod integration with their car stereos.

GM and Ford are the top two car makers in the US, so the new deals will help the iconic audio gadget towards even greater dominance of the portable audio market. The iPod already has a 75 per cent share of the US market.

The iPod will now be compatible with more than 70 per cent of the new 2007 model vehicles sold in the US, according to Apple.

GM and Mazda will offer iPod integration on all new models, and Ford will include it in many models later this year.

BMW incorporated iPods directly into its car stereo systems two years ago, allowing users to access their music library through the car's standard controls. Last year, Apple inked similar deals with car companies including Audi, Ferrari, Honda, Nissan and Volkswagen.

Sales of iPods and other MP3 players are predicted to more than double over the next few years, from 58 million units in 2005 to 132 million in 2009.

The move is part of increasing effort by Ford and other car makers to facilitate drivers’ access to gadgets such as mobiles and satellite navigation systems while they’re on the road.

"Consumers want to engage in all those activities in their vehicles but in a safe manner," said Ford's electronics product and business development director Doug Van Dagens.