OpenAM provides open source Authentication, Authorization, Entitlement and Federation software.
The OpenAM documentation itself is not complete as the original OpenSSO.
OpenAM Documentation - http://openam.forgerock.org/
Video for setup and quick install guide - https://wikis.forgerock.org/confluence/display/openam/Deploy+OpenAM
Another Documentation Site, looks to be more complete but at the same time older - https://wikis.forgerock.org/confluence/display/openam/OpenAM+Installation
OpenSSO Documentation - http://docs.oracle.com/cd/E19681-01/index.html