How to automatically login corporate / internal users to Internet or Extranet website

I have often been faced with this challenge of automatically logging in internal organizational users to intranet accessed via a public URL. For example IE 6.0+ will be able to automatically login a user to the Intranet accesssed via the internal URL (like http://intranet) but the same internal corporate user will be prompted for a username/password when trying to access the same intranet site via the public facing external URL (like http://intranet.xyzinc.com). I solved this issues by merging the following registry entries at each of the user's computer and this can be automated by including the script below as part of the user's logon script to the domain (my example below assumes that your external public facing url is intranet.xyzinc.com for your internal corporate intranet hosted on a web server named MOSS01):

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap\Domains]@=""
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap\Domains\xyzinc.com]
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap\Domains\xyzinc.com\intranet]"*"=dword:00000001
[HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ZoneMap\Domains\MOSS01]"*"=dword:00000001