Microsoft and Research in Motion (RIM) announced in March 2011 that RIM will provide a hosted BlackBerry service for Office 365 customers, known as BlackBerry Business Cloud Services. Blackberry Business Cloud Services will provide BlackBerry users with email, calendar, PIM, and additional capabilities. A public beta is expected to be available in early October. RIM has made available some publicly-facing resources for customers and partner audiences in regard to their future services for Office 365. 

You can read more about the service description at http://docs.blackberry.com/28623