You can now download the first couple of guides (word docs) for Exchange 2007.
Deploying a Standard Exchange Server 2007 Organization: http://go.microsoft.com/fwlink/?LinkId=82170
Deploying a Simple Exchange Server 2007 Organization: http://go.microsoft.com/fwlink/?LinkId=82171
Deploying a Large Exchange Server 2007 Organization: http://go.microsoft.com/fwlink/?LinkId=82172
Deploying a Complex Exchange Server 2007 Organization: http://go.microsoft.com/fwlink/?LinkId=82173
Additional guides will be released in the near future.