The JOS Explorer is a Swing based application that runs both under JOS and under a host OS (Windows, Linux ...). It displays the file system as a tree structure. You can delete, rename, copy... anything you normally want to do with files.
A preview of JOS Explorer was released during the ShowYourWaresWeek at FilesystemCode.
A sad thing is that we probably can't distribute JOS Explorer with JOS 1.0 since we need a FreeSwing first. But it will be great for testing the JOS file system under your favorite OS.