Infrastructure Planning and Design guide for Windows Server 2008 Terminal Services, or the TS 2008 IPD for short, is a great document that teaches you a lot about Terminal Services in 2008. This is the chapter selection that Microsoft is thinking about:

• The Planning and Design Series Approach
• Introduction
• Terminal Services in Microsoft Infrastructure Optimization
• Windows Server 2008 Terminal Services Design Process
• Step 1: Determine the Scope  of the Presentation Virtualization Project
• Step 2: Determine Which Applications to Deliver and How They Will Be Used
• Step 3: Determine Whether Terminal Services Can Deliver Each Application
• Step 4: Categorize Users
• Step 5: Determine the Number of Terminal Server Farms
• Step 6: Map Applications and Users to Farms
• Step 7: Design the Farm
• Step 8: Determine Where to Store User Data
• Step 9: Size and Place the Terminal Services Role Services for the Farms
• Step 10: Secure the Communications
• Conclusion
• Appendix A: The User and Application Data Job Aid  
• Appendix B: The Application Analysis Job Aid  
• Appendix C: The Farm Design Job Aid
• Appendix D: Server Performance Analyzing and Scaling

It holds a schematic representation of the Windows Server 2008 Terminal Services components and how they relate to each other. Already one of my favorites.

I especially like Appendix D that provides some good information for early adopters. But the entire 65 page document is worth reading. Be sure to sign up for the Infrastructure Planning and Design guide for Windows Server 2008 Terminal Services Beta on Microsoft Connect and provide the authors with your feedback.