Owners of Ford, Mazda and GM cars who want to take their iPods on the road may no longer have to worry about purchasing quirky add-ons like the iTrip or chargers that plug into cigarette lighters. Apple announced on Thursday that it has teamed up with the three car companies to incorporate "seamless integration" into new 2007 models that will let iPods be controlled within cars' audio systems and charged whenever the ignition is on.

The plans and infrastructure for iPod integration differ among the three manufacturers. Ford, for example, will be incorporating audio input jacks compatible with the iPod and other MP3 players into a majority of 2007 Ford, Lincoln and Mercury models. For an additional price, beginning early next year, Ford dealers plan to begin selling a system called TripTunes Advanced that will enable an iPod to be stored and recharged in a vehicle's glove compartment while the driver or passenger directs its functions using controls on the radio or steering wheel.

GM, on the other hand, has developed an iPod-specific device called the Personal Audio Link. This gadget, the size of a deck of cards, synchronizes the music player with the car's XM Satellite Radio band so that the XM interface can be used as controls--including displaying the song and artist information on the XM screen.

Like Ford's TripTunes Advanced, GM's iPod integration system will be located in the glove compartment and will also be able to charge the iPod while the ignition is running. The Personal Audio Link will make its debut this October in the 2006 and 2007 Chevrolet HHR sport utility vehicles; the carmaker will then gradually introduce the hardware into all 56 of its new car and truck models sold in the United States--mostly by the end of 2007.

GM's device will be an opt-in feature, retailing for about $160 plus installation charges. According to a statement from GM, a subscription to XM Satellite Radio will not be required for the Personal Audio Link to work.

Mazda, which will be introducing iPod integration into all of its vehicles worldwide, was not available for a comment on the specifics of the technology used.

A number of other car manufacturers, both domestic and foreign, have already accommodated some or all of their new models to allow for iPod integration--among them are DaimlerChrysler's Jeep, Volkswagen, BMW and its Mini, and Honda Motor. With the addition of Ford, Mazda and GM, Apple estimates that more than 70 percent of new cars sold in the United States by the end of 2007 will have some kind of iPod integration technology.