Handles.color  

static var color : Color

Description

Colors of the handles

Magenta slider that points to 0,0,0.

// Simple script that creates a Magenta Slide Handle that 
// points to (0,0,0) nomatter where the target GameObject is located.

@CustomEditor (Slide)
class SliderHandleJS extends Editor {
    function OnSceneGUI () {
        Handles.color = Color.magenta;
        target.vectorPoint = Handles.Slider (target.vectorPoint, 
                              Vector3.zero - target.transform.position);
        if (GUI.changed)
            EditorUtility.SetDirty (target);
    }
}

And the script attached to this Handle:

// Usage: Place this script on the Game Object you want to use the
// editor-created slide handle.

@script ExecuteInEditMode()

var vectorPoint : Vector3 = Vector3(0,0,0);

function Update() {
    Debug.Log("Looking at: " + vectorPoint);
}