See the link below for a great script that uses Powershell to determine when Active Directory passwords will expire.  Web Active Directory, LLC also has a product called PeopleMinder that automates the notification of your end users, specific user groups, etc of an upcoming Active Directory password expiration, but if you want to make your own script here’s a great start at that.

http://blogs.msdn.com/adpowershell/archive/2010/02/26/find-out-when-your-password-expires.aspx

For more information contact us at www.webactivedirectory.com, or call us at (+1) 800-747-3565