If you are interested in a checking out Web Browser SSO using SAMLv2.0 on JBoss or Tomcat, try JBoss Identity 1.0.0.alpha3 from:
JBoss Identity Project
The documentation is available from the wiki and guides.
You can also try Oasis WS-Trust v1.3 SAML Token Profile support using the JBoss Security Token Service.
We are very eager to get your feedback in the user forum.