I've just begun a project involving an Exchange 2007 deployment on Windows 2008, one FE (Hub and CAS roles) with a clustered BE (Mailbox role only), the Edge role will be Sendmail.
This is an intra-organization migration replacing a single Exchange 2003 server. Part of this is getting the prerequisites out of the way. TechNet has a couple of great articles, Preparing AD and Domains and Installing Exchange 2007 Prerequisites on Windows Server 2008.
So far so good. I'm also making use of Jim McBee's great book Exchange 2007 Implementation and Administration as well (this book assumes that you have experience with Exchange, Windows Server and Active Directory).
I'll post more as the project progresses.