By Emily Knapp

Apple (AAPL) wants us take its popular virtual assistant Siri along for the ride. So far there has been no shortage of automakers willing to be guinea pigs for Apple's new Eyes Free feature, which will essentially replicate the iPhone's Siri button on car steering wheels, allowing drivers to converse with Siri through car speakers.

But while Audi, BMW, Chrysler, Honda (HMC), General Motors (GM), Jaguar, Land Rover, Mercedes and Toyota (TM) have already agreed to integrate the feature, Ford (F) was noticeably absent from the list of willing participants presented at Apple's Worldwide Developers Conference on Monday.

Ford's reluctance may have something to do with Apple's unabashed encroachment on automakers' territory. Ford happens to be the most aggressive car manufacturer when it comes to integrating connected car technologies such as voice command and control, and the iPhone is a core device in its Microsoft (MSFT)-powered connected car platform Sync, which requires a smartphone to connect to the Internet and host the apps Sync runs. But now Apple is trying to take that control away from automakers while pushing its own exclusive integrated features. (Microsoft owns and publishes Top Stocks, an MSN Money site.)

Here's how Apple describes Siri's Eyes Free capabilities:

...you’ll be able to ask Siri questions without taking your eyes off the road. To minimize distractions even more, your iOS device’s screen won’t light up. With the Eyes Free feature, ask Siri to call people, select and play music, hear and compose text messages, use Maps and get directions, read your notifications, find calendar information, add reminders, and more. It’s just another way Siri helps you get things done, even when you’re behind the wheel.

Ford likely had some qualms about the navigation feature, which doesn't access its own vehicle navigation system and services, but rather taps into Apple's new Maps service, which was unveiled at WWDC and will be released with iOS 6 this fall. Meanwhile, Ford's own Sync replicates features such as dictating text messages, playing stored music, and reading back notifications -- all of which Ford has every interest in keeping in its own dashboard rather than ceding them to the iPhone.

Of course, Ford doesn't make any revenue off a dictated email, but Ford is now turning Sync into a platform for which third-party developers like Pandora (P) can develop apps that take advantage of its voice command capabilities, display, and dashboard controls. By ceding even basic functions like message notifications to Siri, Ford weakens that platform and gives Apple room to take over that space.

As Americans grow increasingly connected, a wired vehicle may become the next must-have, and Apple and Ford are in a nascent struggle to position themselves at the front of the crowd before the real race begins.

Shares of Ford Motor are closed lower 6 cents at $10.35, while shares of Apple closed $2.60 higher at $574.13 on Friday.

Emily Knapp is an editor at Wall St. Cheat Sheet. As of this writing, she did not own a position in any of the aforementioned stocks.

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