Any window in Blender can be turned into a Scripts Window.
At the bottom left corner (or sometimes top left) of a window you will see a button for a combo box that changes the window type.
Click that and select Script Window. (The one with the snake icon - for Python scripting.)
You can also split windows if you want to make an extra one. So you could split the main 3d window, and turn the new one into your script window, and still have all your other ones as normal.
 actually Blender 2.5x doesn't have a snake icon, its got a console cursor icon, and the window is called Python Console instead of Script Window.
But I'm guessing you're using trusty ol' 2.4x as most of the stable Ogre related scripts work with that version. 2.5x is fairly new. Ok I just checked the link you cited, and you will need 2.4x for that. There are a few newer versions in the works, but I don't think any is quite ready yet.