The setting for showing the free shipping icon applies to both the product listing and product info pages, so you will have to make a small code edit to hide it in the listing only.
In /includes/modules/your_template/product_listing.php around line 145, find this
PHP Code:
$lc_text .= '<br />' . (zen_get_show_product_switch($listing->fields['products_id'], 'ALWAYS_FREE_SHIPPING_IMAGE_SWITCH') ? (zen_get_product_is_always_free_shipping($listing->fields['products_id']) ? TEXT_PRODUCT_FREE_SHIPPING_ICON . '<br />' : '') : '');
break;
case 'PRODUCT_LIST_QUANTITY':
and comment out the $lc_text line with //
to get
PHP Code:
// $lc_text .= '<br />' . (zen_get_show_product_switch($listing->fields['products_id'], 'ALWAYS_FREE_SHIPPING_IMAGE_SWITCH') ? (zen_get_product_is_always_free_shipping($listing->fields['products_id']) ? TEXT_PRODUCT_FREE_SHIPPING_ICON . '<br />' : '') : '');
break;
case 'PRODUCT_LIST_QUANTITY':