Microsoft Training Links

Microsoft Virtual Labs
http://technet.microsoft.com/en-us/virtuallabs/bb499043

Microsoft Virtual Academy
http://www.microsoftvirtualacademy.com

Blogs
http://smtp25.blogspot.ca/
http://www.msexchangegeek.com

Exchange 2013
Exchange 2003 Prerequisites
http://technet.microsoft.com/en-us/library/bb691354(v=exchg.150).aspx

Here is a great link to setting up an Exchange 2010 DAG.
http://www.exchange-genie.com/2009/04/database-availability-group-dag-exchange-2010/

Certs:
http://www.msexchangegeek.com/2009/05/13/exchange-2010-emc-and-certificates-management-part-1/

Exchange 2010 Service Pack and CU Release Dates
http://technet.microsoft.com/en-us/library/hh135098(v=exchg.141).aspx