How to make the main menu expanded? I have set main menu items expanded but when I print them in page.tpl.php($main_menu) there are no children for menu items.How can I make them expanded?
Go to admin/structure/menu/manage/main-menu and edit the parents that have children that you wish to show, and click the tickbox 'show expanded'

Or alternatively install the module http://drupal.org/project/menu_expanded which brings back the tickbox on the menu 'list items' page ala drupal 6

Hope this helps