I haven't tried to use the NXT simulator yet, but I plan on doing it soon. I'm wondering if its possible to use something such as leJOS in place of the standard NXT OS with the simulator?

http://lejos.sourceforge.net/

Our simulation only works with Microsoft Robotics Developper Studio. Actually, the code doesn't run on the robot but on your computer, communication with robot is done by bluetooth and there is no use of NXT OS.
The cool feature is that you can run the same code on simulation and on the real robot without modifications.

You say that you can use the same code on both the actual robot and on the simulation, I'm asking if it's possible to set up the java OS "leJOS" (which is a full firmware replacement for the NXT OS) with the simulation?

If your running the code with the simulation, I'm assuming that code is meant to run on the NXT OS; I would like to be able to use leJOS instead.

Is it possible to edit the structure of the robot on the simulation?

It's not easly possible. You have to "emulate" the lego brick I think



The code is not running on NXT OS. The code runs on your computer (XP or Vista with Robotics Studio) and only send and receive basic information from the robot by bluetooth



For now, only the tribot model is available. Maybe we will release more 'classic' models like AlphaRex. If you want to simulate you own custom robot, it's possible with MSRDS but it requires to make you own 3D model and to code the physics model.

Regards