The Windows Server 2008 R2 Certificate Enrollment Web Services Whitepaper has been posted to the download center: you can download it here.

This is just the initial document release for RTM.  We plan to publish the content to various Technet locations in the next several months, and we will have some opportunity to revise or update the content as part of that process.

Topics covered in the paper:

Business Scenarios
Renewal only mode description
Designing the infrastructure
-Network and Firewall requirements
-Delegation requirements
-Performance and throughput
-Client Behavior / Load Balancing
Deployment
-Installation Prerequisites
-Supported configurations
-Setup Step-By-Step
Troubleshooting and Diagnostics

Please let me know if you have questions/feedback: jfield@microsoft.com