mailboxGoogle announced today that it is launching a service called Google Message Community that will serve as disaster insurance for Microsoft Exchange users, backing up their email and contact data into Google applications.

The search giant isn’t one to shy away from pulling business from Microsoft and its Exchange products. In fact, it even offers a service to directly transition from Exchange over to Google’s enterprise applications.

So why is Google warming up to Microsoft now? Well, this could be another chance for Google to get its enterprise products in the hands of potential customers. If a Microsoft Exchange server goes down, Google Message Community users can log into Gmail and Google Calendar and move on with their lives. The hope is probably that users will see Gmail as a little more reliable than Microsoft Exchange, and make the switch.

And that reliability can be critical for larger businesses that rely on Microsoft Exchange servers and a consistent email service. Email outages can cost larger businesses upwards of $90,000 every year, according to Osterman Research. For smaller companies using Microsoft Exchange, an email outage can mean losing the company’s (possibly) only communication tool.

The service will cost $25 per user per year, or $13 per user per year for current Postini users. The backup service stems from Google’s acquisition of Postini, a provider of security for email in a cloud environment, back in 2007. Google paid $625 million for the company when it didn’t have a very robust suite of enterprise applications.