function si_open( theURL )
{
   _width = 640;
   _height = 549;

   _top = (screen.height-_height)/2;
   _left = (screen.width-_width)/2;

   window.open( theURL, "Show","width="+_width+",height="+_height+",alwaysRaised=yes,dependent=yes,top="+_top+",left="+_left );
}