You’ll find a brief overview of Terminal Services features in Windows Server 2008 at http://www.microsoft.com/windowsserver/2008/evaluation/overview.mspx. By the time you read this chapter, this site will probably redirect you to something with a lot more content.
If you have access to the Windows Server 2008 beta program on Microsoft Connect (http://connect.microsoft.com), you can get some great Terminal Services documents from there, including:
Windows Server 2008 Terminal Services RemoteApp Step-by-Step Guide
Windows Server 2008 Terminal Services TS Gateway Server Step-by-Step Setup Guide
Windows Server 2008 Terminal Services TS Licensing Step-by-Step Setup Guide
Plus you’ll also find chats there, saved Live Meeting presentations, ...