JBoss Modules is itself a much better example. If you're just looking to use it (from an end-user perspective), then the AS7 module repository is a good example of laying out how modules are assembled.
If you want to define your own module loader, look at the LocalModuleLoader and other implementations (though beware that the ModuleLoader API might change a little before things are final). Also, he Modules test cases have some good examples of building up a ModuleLoader programmatically.