How to change the logo text.
   


To customize the logo string you will have to use a property named logoString. Here is a simple sample:
  Properties props = new Properties();
  props.put("logoString", "my company");
  AeroLookAndFeel.setCurrentTheme(props);
  UIManager.setLookAndFeel("com.jtattoo.plaf.aero.AeroLookAndFeel");
                                

See also:

How to change the theme.
How to use a predefined theme.