Apache MyFaces provides an implementation of the JSF specification ("MyFaces Core"), and a set of add-on libraries that work on any implementation of the specification.
Apache MyFaces is a Java Server Faces(JSF) implementation. It is a project of Apache Software Foundation and holds many sub-projects. All MyFaces frameworks, UI Libraries, components and extensions are based on MyFaces Core that has two submodules MyFaces API (myfaces-api.jar) and MyFaces Impl (myfaces-impl.jar). Following are the some information of some MyFaces sub-projects:
Trinidad : A framework that provides a large set of enterprise quality components. Project Site and Demo Site.
Tobago: It provides rich set of JSF based UI Components. The UI Components are abstracted from HTML. It also provides theming mechanism and a layout manager. Project Site and Demo Site.
Tomahawk: It is a set of JSF components that go well beyond the JSF specification. The Tomahawk family of components includes converters, validators, and a set of attributes added to the JSF components. Project Site and Demo Site.
Find more information on MyFaces on The Apache MyFaces main site. A good source of information can also be found on this site. A good starter tutorial can be found at this site. There is also a reference in Wikipedia.