I have started modifying this code on the tpl_advanced_search_default.php page:

PHP Code:
<div class="floatLeft"><?php echo zen_draw_pull_down_menu('artists_id', zen_get_categories(array(array('id' => '', 'text' => TEXT_ALL_CATEGORIES)),0 ,'', '1')); ?></div>
I'm not sure how to modify
PHP Code:
zen_get_categories 
to list the artists from the database.

Can you help?