It seems, Today morning SCCM ConfigMgr 2012 has been released for MSDN and TechNet subscribers. Also released for Volume License customers. Following are the details I can see in the TechNet subscription page. More details here. Download the eval version of SCCM 2012 (ConfigMgr 2012) R2 from Microsoft’s eval center here.
Also checkout ConfigMgr SCCM 2012 SP1 to R2 Upgrade Checklist
System Center 2012 R2 Configuration Manager (x86 and x64) – DVD (Multiple Languages)
ISO|Multiple Languages|Release Date: 10/17/2013