Microsoft has now released Exchange Server 2007 Service Pack 3.
With SP3 it is now possible to run Exchange 2007 on Windows Server 2008 R2.
Download Exchange 2007 SP3 from here
The link with what’s new in Exchange seems to be incorrect. but here it is anyway http://go.microsoft.com/fwlink/?LinkId=154404
Don’t run of and upgrade your OS to Windows Server 2008 R2 because of this. It’s most likely not supported when Exchange is installed.
Happy patching