I missed this yesterday, but RIM announced support for Exchange Server 2010 on their site here http://na.blackberry.com/eng/support/software/server_compatibility.jsp#tab_tab_news.
October 20, 2009 - Research In Motion (RIM) is pleased to notify you that we are working in close collaboration with Microsoft on compatibility and support for BlackBerry® Enterprise Server for Microsoft® Exchange Server 2010. Compatibility is expected later this year. BlackBerry® Technical Support Services for BlackBerry Enterprise Server for Microsoft Exchange Server 2010 is expected within 30 days following the global availability of Microsoft Exchange Server 2010.
Daniel