Hi Folks,
RU 1 was released ( http://support.microsoft.com/kb/976573) and BES is also fully supported on Exchange Server 2010.
Read more at source: http://msexchangeteam.com/archive/2009/12/09/453486.aspx and http://msexchangeteam.com/archive/2009/12/09/453485.aspx
Cheers,
Anderson Patricio