Start with the JSF2 DataSheet.
Once you've read that, continue here. As a developer writing JSF applications, you have a myriad of options available for documentation and help. One of the best places to start is with the official documentation. The user documentation is available as part of the Java EE 7 tutorial.
At the time of writing, the current version of the specification is 2.3. Additions and changes relatively to the previous version (2.2) are described in What's new in JSF 2.3.
API documentation is also available for the 2.3, 2.2, 2.1, 2.0, 1.2, and 1.1 versions of the specification:
- JavaServer Faces 2.0
- JavaServer Faces 1.2
- JavaServer Faces 1.1
- Ed Burns' Blog
- Roger Kitain's Blog
- Ryan Lubke's Blog
- Jacob Hookom's Blog #1
- Jacob Hookom's Blog #2
- Jason Lee's Blog
- Marty Hall's JSF 2.0 tutorial
The Mojarra libraries and sources can be downloaded here.
The Sun JSF Team has given many presentations over the years, some of which are available from our presentations site.For more links, you can reference the sidebar conveniently located on the front page for easy reference.
As with any technology, management is often very much interested in support. Since JavaServer Faces is a technology, and not a product, paid support directly for JavaServer Faces is not available from Sun. Paid support may be available, however, from the Application Server vendor that includes JavaServer Faces technology, for example, the Sun Java System Application Server.
That is not to say, though, that support is not available. The javaserverfaces project here on java.net is a community-supported open development product. One of the best venues for getting your questions answered is the Mojarra (and general webtier) Discussion Forum about JavaServer Faces Technology. Another excellent choice is the ##jsf channel on the Freenode IRC network (irc.freenode.net). Many core developers try to spend time there, and there is an active and growing community of fellow JSF users like yourself who are willing and able to help. There are also mailing lists available for discussion. Those can be found here