I have written a small script that check if account passwords are about to expire. If they are, you get a event in the local event viewer. You can pick up that event with Ops Mgr and MOM and then generate a alert for your operators and/or administrators. You can download the script here.
Default settings are that you will get a event if the password will expire within 20 days and the script checks all user objects within this OU OU=Service Accounts,OU=Contoso EMEA,DC=emea,DC=corp,DC=contoso,DC=local