There's some new content from MS IT Showcase on how Microsoft uses Exchange 2007's Edge Transport server in production. Check out the white paper and PowerPoint presentations below.
Microsoft Exchange Server 2007 Edge Transport and Messaging Protection
In deploying the Exchange 2007 based messaging protection solution, Microsoft IT used all messaging protection features of the Edge Transport server role and Forefront Security for Exchange Server to block, delete, reject, or quarantine unwanted messages. To further increase security, servers were hardened and audited for vulnerabilities to ensure readiness for Internet visibility. The many steps that Microsoft IT took to design a network environment, combined with the messaging protection features of Exchange Server 2007, resulted in greater flexibility, fewer false positives, and reduced TCO.Technical White Paper | PowerPoint Presentation
Scott has just pointed to a whole new set of Exchange 2007 documentation that has just been released