Exchange 2007 and IPv6 compliance; this is a topic that comes up quite often. People want to know what they need to install to make this work.
In order to get IPv6 running on Exchange Server 2007, you will need to meet a few requirements. First of all, you need Service Pack 1 for Exchange. Secondly, Exchange needs to be installed on Windows Server 2008. Although Exchange Server 2007 can be installed on Windows Server 2003, it will not have IPv6 support unless it is installed on Windows Server 2008. Finally, Exchange Server 2007 requires a 64-bit server. In other words, to get Exchange running with IPv6, you will need:
Exchange Server 2007 Service Pack 1 running on Windows Server 2008 (64-bit)
Update: see http://technet.microsoft.com/en-us/library/bb629624.aspx for more detailed information from the Exchange team!