Help me please arcpy will not initiallize

Using Python Idle

typed in

import arcpy

get error below

Traceback (most recent call last):
File "<pyshell#3>", line 1, in <module>
import arcpy
ImportError: No module named arcpy


using

Python 2.7.3 (default, Apr 10 2012, 23:24:47) [MSC v.1500 64 bit (AMD64)] on win32

using Arcis 10.1

thank you