JRDF GUI 0.1 Release. Assuming Java 1.5, just download the jar and double click or type: "java -jar jrdf-gui-0.1.jar". This is what I was talking about recently.
Updated: I have fixed a couple of bugs and re-released the binary. This was to do with loading graphs from the user interface - re-creating the graph each time and making sure the file URI is properly escaped.