Prof. Frank Zimmermann from the Nordakademie polytechnic in Elmshorn, Germany, has published an Eclipse plugin that allows you to graphically model NXT applications based on statemachines and generate code from it that can be run on the brick (based on leJOS NXJ).
Very interesting approach and the only NXT language next to NXT-G (and maybe the VL contained in Microsoft's Robotics Studio) with a graphical syntax.
As an additional (quite helpful debugging) feature, you can even use the diagram to watch the execution of the program on the NXT!
The whole thing can be seen live also on the OOP in Munich next week at Gentleware's booth.
Update: a video of the plugin in action on the OOP can be viewed here.