Spring is a powerful framework for building enterprise Java applications. JSF is a standards-based technology that can simplify Web development. It is possible to combine the two with surprisingly little effort, allowing developers to take advantage of the best that both Spring and JSF have to offer. Check this useful article By Michael Klaene which demonstrates how to utilize JSF and Spring to build an application. Which also contains a very brief overview of both JSF and Spring .
Spring to Java Server Faces By Michael Klaene