When collider enters trigger, colliders parent = triggers parent

I'm trying to write some code so that when a gameObject enters a Trigger, it parents that gameObject to the triggers own parent. However, I'm having some difficulty accessing the Transform of said object in my code. Here's some examples of what I've tried:

function OnTriggerEnter (other : Collider){
if (other.transform.tag == "Moveable")
    {
    other.transform.parent = transform.parent;
}
}

And:

var otherTrans;
function OnTriggerEnter (other : Collider){

if (other.transform.tag == "Moveable")
    {
    otherTrans = other.transform;       
    otherTrans.parent = transform.parent;

}
}

I've tried a few other things too, but they're all variations on this. I've tried looking through the script references for inherited members, but I still can't find a way. What is the exact set of inherited members I need, or does my code need changed?

Thanks

P.S. all the colliders which it would pick up are rigidbodies.

Your first code example will work as-is, although you don't need to get the tag from the transform component (it's inherited from GameObject anyway), and using CompareTag is better.

if (other.CompareTag("Moveable")) {

Put Debug.Log statements in to see if the trigger event is happening, and what the other's tag actually is.