Alert user Pending password expiration

Question

I am looking remind users to change their passwords ahead of time.
I am manually checking the passwords every day. Group policy is not an option in this case.
I need to alert the user by email that their Active Directory password will expire in x day's
This would query a specific OU
Im looking for this myself, I have no scripting knowledge but eager to learn.
Has anyone done this already?
Thanks for reading
confuseis

Answer 1

That looks good Thanks. 
Only thing is that I would need to run this against a specific OU, infuse this with the script below?
e.g. Ou=Users,Ou=London,DC=WestEurope,DC=Contoso,DC=com
# Please Configure the following variables....
$smtpServer="mail.server.com"
$expireindays = 21
$from = "Company Administrator <[email protected]>"
#Get Users From AD who are enabled
Import-Module ActiveDirectory
$users = get-aduser -filter * -properties * |where {$_.Enabled -eq "True"} | where { $_.PasswordNeverExpires -eq $false } | where { $_.passwordexpired -eq $false }
foreach ($user in $users)
  $Name = (Get-ADUser $user | foreach { $_.Name})
  $emailaddress = $user.emailaddress
  $passwordSetDate = (get-aduser $user -properties * | foreach { $_.PasswordLastSet })
  $PasswordPol = (Get-AduserResultantPasswordPolicy $user)
  # Check for Fine Grained Password
  if (($PasswordPol) -ne $null)
    $maxPasswordAge = ($PasswordPol).MaxPasswordAge
  else
    $maxPasswordAge = (Get-ADDefaultDomainPasswordPolicy).MaxPasswordAge
  $expireson = $passwordsetdate + $maxPasswordAge
  $today = (get-date)
  $daystoexpire = (New-TimeSpan -Start $today -End $Expireson).Days
  $subject="Your password will expire in $daystoExpire days"
  $body ="
  Dear $name,
  <p> Your Password will expire in $daystoexpire days.<br>
  To change your password on a PC press CTRL ALT Delete and chose Change Password <br>
  <p>Thanks, <br>
  </P>"
  if ($daystoexpire -lt $expireindays)
    Send-Mailmessage -smtpServer $smtpServer -from $from -to $emailaddress -subject $subject -body $body -bodyasHTML -priority High
confuseis