Download Exchange 2010 SP1 here : http://go.microsoft.com/fwlink/?LinkID=199950
For Windows Server 2008 R2 the following hotfixes are required :
- http://code.msdn.microsoft.com/KB982867/Release/ProjectReleases.aspx?ReleaseId=4520
- http://code.msdn.microsoft.com/KB983440/Release/ProjectReleases.aspx?ReleaseId=4410
- http://code.msdn.microsoft.com/KB977020/Release/ProjectReleases.aspx?ReleaseId=4115
- http://code.msdn.microsoft.com/KB979744/Release/ProjectReleases.aspx?ReleaseId=3993