Use the Drupal module Menu Firstchild to create menu items without links

By default, Drupal requires that you enter a path for each menu link you add/edit from the Menu administration page. There are cases you may want to create a parent item, without any path, that simply links to its first viewable child item. Menu Firstchild provides this functionality.

Another similar solution (didn't worked smoothly in all cases): Special menu items

Taxonomy: 

Drupal themes to be compared