go into the customer/categories.tpl go to the last line:
Code:
{ include file="menu.tpl" dingbats="dingbats_categorie.gif" menu_title="Categories" menu_content=$smarty.capture.menu cellpadding=$fc_cellpadding}
and replace it with:
Code:
{ include file="menu.tpl" dingbats="dingbats_categorie.gif" menu_title="Music Genres" menu_content=$smarty.capture.menu cellpadding=$fc_cellpadding}
That should take care of just the categories title.