Microsoft has a blog series called MVP Mondays. I was asked to be a guest author and to write a blog about Office 365. Check out my most recent blog on changing your MX record to FOPE in an Exchange Hybrid configuration, created from Exchange 2010 SP2. This blog highlights some key changes that are necessary in FOPE, to maintain a Hybrid configuration, but have Exchange Online be the destination for all incoming mail.
http://blogs.msdn.com/b/mvpawardprogram/archive/2012/05/04/changing-your-mx-record-to-fope-in-an-exchange-hybrid-configuration-created-from-exchange-2010-sp2.aspx