Andrei Cioroianu has written a very good article on how to use the MyFaces File Upload component: http://www.onjava.com/pub/a/onjava/2005/07/13/jsfupload.html
Note that the name of this component is <t:inputFileUpload>.
You also must set the enctype properly on your containing form as well as use the extensionsFilter.
<h:form enctype="multipart/form-data">
This post on the user list shows how to use the file upload component: http://www.nabble.com/Tomahawk-1.1.3-inputFileUpload-solution-t2318350.html