Google acquired Postini back in 2007, and since then, it has slowly transitioned features from the hosted security and archiving service into Google Apps.

Google provided an updated today about the plan moving forward, as it plans to have Postini fully transitioned into Google Apps by the end of next year.

“In the past two years, we developed and released numerous Postini features directly in Google Apps, such as user policy management; email content filters; archiving, retention and eDiscovery with Google Apps Vault; and many more,” says product manager Adam Dawes. “As we look ahead to 2013, we’ll continue these feature integrations and gradually transition Postini Google Message Security (GMS) and Google Message Discovery (GMD) customers to Google Apps. This will enable them to take advantage of the Postini features built directly into Google Apps that are more flexible, powerful and user-friendly.”

Google Apps admins can start using a new feature to manage routing and basic filtering of email to on-premis systems (as well as email to Google Apps users) starting today.

“This feature will make it easier for groups like sales, support and operations to use generic email addresses such as sales@ or support@,” says Dawes. “Messages to these addresses typically need to be routed to ticketing or alerting systems outside of Gmail, and now Google Apps has the capability to define routing rules to get these messages to their proper destinations.”

As far as the full transition goes, Google says Postini users don’t have to worry about doing anything yet, but warns that change is coming, and it will give users info about migrating in time.

More info about the transition here.