If it's of any use, here's what someone wrote at our place and we deployed through the login script:
Batch file to call the vbscript:
@echo off
if not "%OS%" == "Windows_NT" goto skip
if exist "%systemdrive%\documents and settings" goto doit
goto skip
:doit
title xxx Banner deployment
cscript//nologo \\server\sys\public\banner\banner.vbs
goto end
:skip
echo Skipping banner deployment...
:end
And the VBScript:
' xxx date
Set WshShell = WScript.CreateObject("WScript.Shell")
Dim capToken, capValue, txtToken, txtValue
capToken = "HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\LegalNoticeCaption"
capValue = "Warning: Use of this System is Restricted to Authorized Users"
txtToken = "HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Winlogon\LegalNoticeText"
txtValue = "This computer system is the private property of the Company, blah, blah, blah"
WshShell.RegWrite capToken, capValue
WshShell.RegWrite txtToken, txtValue
There's probably better ways of doing it, but this works for us!