Transform.parent

var parent : Transform

Description

The parent of the transform.

Changing the parent will modify the parent-relative position, scale and rotation but keep the world space position, rotation and scale the same.

JavaScript
    // Makes the camera follow this object by
// making it a child of this transform.
// Get the transform of the camera
var cameraTransform = Camera.main.transform;
// make it a child of the current object
cameraTransform.parent = transform;
// place it behind the current object
cameraTransform.localPosition = -Vector3.forward * 5;

// make it point towards the object
cameraTransform.LookAt(transform);

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
public Transform cameraTransform = Camera.main.transform;
void Example() {
cameraTransform.parent = transform;
cameraTransform.localPosition = -Vector3.forward * 5;
cameraTransform.LookAt(transform);
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

public cameraTransform as Transform = Camera.main.transform

def Example():
cameraTransform.parent = transform
cameraTransform.localPosition = ((-Vector3.forward) * 5)
cameraTransform.LookAt(transform)

Another example:
JavaScript
    // Detaches the transform from its parent.
transform.parent = null;

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
void Example() {
transform.parent = null;
}
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

def Example():
transform.parent = null