The Exchange Team has just announced the Service Pack 3 for Exchange Server 2010. It is currently scheduled for release in first half of 2013.
The SP3 will as expected include support for Co-existence with Exchange 2013 and also support for installing Exchange 2010 on Windows Server 2012.
Along with these two major features, it will contain all fixes within Update Rollups released prior to SP3.
Read more on the Exchange Team blog about the announcement.