If you get a message like this in your Roles Summary "RollUp" after installing WCF as part of the Application Server Role in Windows Server 2008RC0:

To configure WS-Atomic Transactions, run the wsatconfig.exe utility in C:\Windows\Microsoft.Net\Framework64\v3.0\Windows Communication Foundation using the following certificate thumbprint for the SSL certificate: 53B7DAAA12C8D60FD10908328A45A707C299AAB5

It's saying to go run:

WsatConfig.exe -network:enable -endpointCert:53B7DAAA12C8D60FD10908328A45A707C299AAB5  etc...

Thanks to Jesse for his help.