Like the recently released service pack 1 for ILM 2007 FP1, the new FIM 2010 RC1 update 3 release also includes support for Exchange 2010 provisioning.
And with FIM 2010, it actually works out of the box unlike ILM 2007 which requires you manually change the attributes flow list.
FIM 2010 RC1 Update 3 is the last release before RTM which is scheduled to be released later this year.
Download it here.