Google Apps can now sync with Microsoft's Active Directory or any LDAP user directory like Lotus Domino or the open source OpenLDAP complements of Google's 2007 Postini security acquisition.

The widgetry is called Google Apps Directory Sync and lets Google Apps tap into existing repositories of user account information in hopes of eventually moving them to Google Apps permanently of course.

Google describes the utility as running behind the firewall and pushing directory information to Google Apps - including mailing lists, groups and user aliases - to match the organizational schema in the LDAP system.

It's a one-way operation so data on the LDAP server isn't updated and is said to offer many of the customization settings, tests and simulations originally developed for the Postini directory synch tool.

It's been put in the paid Google Apps Premier, Education and Partner editions for free.