The latest version of Microsoft Exchange Server 2010 is finally available for public download, though it is not available in 32 bit version yet . The current download is the Beta 1. Related documentation can be found at Microsoft TechNet website for further references.
Again, a x64 based product with a lot of modification in the functionality and architecture. Microsoft seems to be moving to .Net 3.5 platform with for Exchange 2010 development. Due to changes in architecture of the product it might look a little different than its previous release; Exchange Server 2007 but it still inherits many feature with much advanced functionality. Key changes in Active Directory Schema, Permissions Model, Mailbox Server role, Routing, High Availability, and much more are the things of interest for those who have already worked on its legacy versions.
So now you can download and enjoy testing 😉