Microsoft Press have released a free ebook called Introducing Windows Server 2012, which does exactly what it says on the tin.
There are three versions available, depending on where you want to read it:
Introducing Windows Server 2012 RTM Edition – PDF ebook
Introducing Windows Server 2012 RTM Edition – ePub format
Introducing Windows Server 2012 RTM Edition – MOBI format
I read the version of this book that was based on the beta and found it very informative. It’s now been updated to the RTM version, so there’s no reason not to grab it now.
Along with the launch of Windows Server 2012* yesterday, Microsoft released the Windows Management Framework 3.0 for some downlevel clients. In the package you get PowerShell 3.0, and updated versions of WMI and WinRM for Windows 7 SP1, Windows Server 2008 R2 SP1 and Windows Server 2008 SP2. If you were looking for support on XP and Vista you are out of luck.
WMF 3.0 also contains the Server Manager CIM Provider that you’re going to need on your 2008 R2 SP1 and 2008 SP2 servers if you want to manage them with the new Server Manager in Windows Server 2012 or Remote Server Admin Tools for Windows 8 (RSAT for Win8 is yet to reach RTM).
Download WMF 3.0 at http://www.microsoft.com/en-us/download/details.aspx?id=34595
* Make sure you click that link to the online launch event; windows-server-launch.com has a load of learning resources for Microsoft’s amazing new Server release, especially around management and virtualisation.