<A target="_blank" href="http://akamai.infoworld.com/t/saas/beware-the-rocky-road-bpos-office-365-169277?source=rss_cloud_computing">You may want to think this one through and talk to Microsoft support</A> before starting anything. If you do it yourself, there's a real risk you will lose e-mail for several days because part of the switch has to be performed on Microsoft's servers.