Admin option sidebar count

If you mean like this

Then here is an handy class to get it done very quickly:

/**
* add_num_to_admin_menu
* @author Ohad Raz <[email protected]>
*/
class add_num_to_admin_menu
{
    public $menus = array();
    /**
     * Class constructor
     * @author Ohad Raz <[email protected]>
     * 
     * @param array $args menu => number format
     */
    function __construct($args = array()){
        if (!is_admin())return;
        $this->menus = $args;
        add_filter( 'add_menu_classes', array($this,'_Add_num'));
    }
    /**
     * the actual function that adds the number to the menu
     * 
     * @author Ohad Raz <[email protected]>
     * @param  array $menu admin menu
     * @return array
     */
    function _Add_num($menu){
        //var_dump($menu);
        foreach ((array)$this->menus as $name => $number) {
            // loop through $menu items, find match, add indicator
            foreach( $menu as $menu_key => $menu_data ) {
                if( $name != $menu_data[2] )
                    continue;
                $menu[$menu_key][0] .= " <span class="update-plugins count-$number"><span class="plugin-count">" . number_format_i18n($number) . '</span></span>';
            }
        }

        return $menu;
    }
    /**
     * Add a number to a menu
     * 
     * @author Ohad Raz <[email protected]>
     * @param string $menu  menu to add the number to
     * @param int $number number to add
     */
    function addMenuNum($menu,$number){
        $this->menus[$menu] = $number;
    }
}

Usage:

//create an instance of the class
$obj = new add_num_to_admin_menu();
//add a number to a menu node
$obj->addMenuNum('edit.php',7);
//repeat as many times as needed
$obj->addMenuNum('upload.php',20);
$obj->addMenuNum('link-manager.php',15);
$obj->addMenuNum('users.php',10);