You Had Me at EHLO just posted some information on Exchange 2007 SP1. This one stood out - it will be a bit before Windows Server 2003 SP2 is implemented. Of course, it will be a bit before Exchange 2007 is implemented! Regarding the operating system, SP1 for Exchange 2007 will require Windows Server 2003 SP2. This will be a hard dependency for installation, so the operating system must be upgraded to Windows Server 2003 SP2 before you upgrade the Exchange 2007 RTM installation to Exchange 2007 SP1,...
Download it here. The list of included fixes is here. Technorati tags: Windows Server 2003 SP2, SP2...