OpenSSO Homepage
SAML v2.0 Technical Overview
http://www.oasis-open.org/committees/download.php/27819/sstc-saml-tech-overview-2.0-cd-02.pdf
Identity Provider Discovery Service Protocol and Profile
http://docs.oasis-open.org/security/saml/Post2.0/sstc-saml-idp-discovery.pdf