As the cadence of Microsoft’s software releases shrinks from the traditional 3 year cycle down to 1 year, a benefit is that the gap between one product being supported on another shrinks as well.
While Windows Server 2012 was released late last year it was only earlier today that Microsoft said that the Directory Synchronization utility for Microsoft Online Services (aka Windows Azure Active Directory) was stated as officially being supported on the now 4-month old operating system.
You can see the official (albeit brief) statement here: http://social.technet.microsoft.com/Forums/en-US/windowsazureaditpro/thread/05d16ddb-11a8-4f93-98cc-c2632e853fb8
Having tested this myself on a Windows Server 2012 member server with another Windows Server 2012 as the domain controller I can safely say this works well and has for over a week now.
For those looking to install the latest bits on a 2012 server there is nothing specific to do or any specific build to get, just click on the Directory Synchronization tool download link inside the Microsoft Online Portal and install it!