Adam Conkle has published some great troubleshooting, tips and tricks and how to articles on TechNet that should help you in evaluating and implementing Active Directory Federation Services.

AD FS - How to invoke a WS-Federation sign-out

AD FS 2.0 - "An unexpected error has occurred" error or blank page displayed attempting to log on to SharePoint, Event ID 23 logged

AD FS 2.0 - The service fails to start. "The service did not respond to the start or control request in a timely fashion. "

AD FS 2.0 - Query notification delivery failed because of the following error in service broker: 'The conversation handle "{GUID} is not found.'

Windows Identity Foundation (WIF) - FedUtil.exe on Windows Server 2003 fails with "Object Identifier (OID) is unknown."

AD FS 2.0 - Prompted for credentials when you are expecting to be allowed anonymous access

Windows Identity Foundation (WIF) - How to change certificate chain validation settings for web applications

AD FS 2.0 - How to set the Primary Federation Server in a WID Farm

AD FS 2.0 - The Admin event log shows Error 111 with System.ArgumentException: ID4216

Windows Identity Foundation (WIF) throws exception: "ID6018: Digest verification failed for reference"

AD FS 2.0 - Browsing to Federation Metadata fails "Unable to download federationmetadata.xml"

AD FS 2.0 - Continuously prompted for credentials when using FireFox 3.6.3

AD FS 2.0 - How to configure the SPN (servicePrincipalName) for the service account

AD FS 2.0 - Continuously prompted for credentials while using Fiddler Web Debugger

AD FS 2.0 - "Script is disabled. Click Submit to continue."

AD FS 2.0 - How to enable and immediately use AutoCertificateRollover

AD FS 2.0 - How to perform an unattended installation of an AD FS 2.0 STS or Proxy

AD FS 2.0 - The AD FS 2.0 Windows Service fails to start - Event 102 and 220 logged

AD FS 2.0 - How to manually run the AD FS 2.0 Initial Configuration

AD FS 2.0 - "ID4037: The key needed to verify the signature could not be resolved from the following security key identifier"

 -- Jonathan "Ned's Blog Monkey" Stephens