Just open up blender, split the main window, pull up the text editor, load the python script (this is the same as with all blender scripts btw), hold your mouse over the text window and hit ALT-P. (if you don't know how to do this yet, you have a bit of reading to do on the blender website) After the script starts, it will pull up a save dialog and you have your ase file.Note that you should get rid of all the cameras and lights in the scene first and also that the model must be scaled quite large in blender to get the right dimmensions after the export.
link again: http://blenderartists.org/forum/showthread?t=45180
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