Use Iphone as sterring wheel

Hello,

My problem is simple.

Imagine you are playing a car video game and you want to use the phone itself as a steering wheel.
I have seen this kind of thing many times.

I found this very good resource :
http://forum.unity3d.com/threads/98828-sharing-gyroscope-controlled-camera-on-iPhone-4

but I am getting a bit mixed up with the mysterious quaternion rotation.
However now, I just want to get one axis rotation from the iPhone Gyroscope(Quaternion) and apply it to the Y axis of my car.
I have been searching ways to convert the gyro data (quaternion) to vector3. Euler…No joy!

I

Quaternion.ToEuler ???

unfortunately this one takes a Euler input and converts to quaternion…from what I understand
I am looking for the opposite. something that would look like this.

var ObjectRotate : Vector3 = QuaternionToEuler(Input.Gyroscope);

Function QuaternionToEuler()
{

}

…but of course I need to fill in the function.

On the other had I find quite stupid to convert a quaternion to Euler so Unity converts it again to Quaternion(since that how it works).
So I am open to any other more elegant solution